一、所适用协定的范围
DSU附件1对此问题进行了规定：
Appendix 1
Agreements Coverel by the Understanding
（A） Agreement Establishing the World Trade Organization
（B） Multilateral Trade Agreements
Annex1A:Multilateral Agreements on Trade in Goods
Annex 1B:General Agreement on Trade in Services
Annex1C:Agreement on Trade-Related Aspects of Intellectual Property Rights
Annex 2:Understanding on Rules and Procedures Governing the Settlement of Disputes
（C） Plurilateral Trade Agreements
Annex 4:Agreement on Trade in Civil Aircraft
Agreement on Government Procurement
International Dairy Agreement
International Bovine Meat Agreement
The applicability of this Understanding to the Plurilateral Trade Agreements shall be subject to the adoption of a decision by the parties to each agreement setting out the terms for the application of the Understanding to the individual agreement, including any special or additional rules or procedures for inclusion in Appendix 2, as notified to the DSB.
（1）《建立世界贸易组织协定》（WTO协定）。该协定主要是规定了成员的总的权利和义务，属于组织性协定，成员方很少依据该协定提起争端。
（2）多边贸易协定。这些协定包括附件1A货物贸易多边协定（《1994关税与贸易总协定》、《农产品协定》、《动植物卫生检疫措施协定》、《纺织品与服装协定》、《进出口许可证协定》、《技术贸易壁垒协定》、《与贸易有关的投资措施协定》、《反倾销协定》、《海关估价协定》、《装船前检验协定》、《原产地规则协定》、《反补贴协定》、《保障措施协定》）、附件1B《服务贸易总协定》、附件1C《与贸易有关的知识产权协定》。这些协定中大都规定了对DSU程序援用的条款，如《农产品协定》第19条、《技术贸易壁垒协定》第14条第1款、《装船前检验协定》第4条、第7条、第8条等。但是也有一些条款，不是援引而是规定了一些特殊、附加的规则和程序，DSU附件2对这些条款进行了列举：
Appendix 2
Special or Additional Rulfs and Procedures
Contained in the Covered Agreements
Agreement Rules and Procedures
The list of rules and procedures in this Appendix includes provisions where only a part of the provision may be relevant in this context.
Any special or additional rules or procedures in the Plurilateral Trade Agreements as determined by the competent bodies of each agreement and as notified to the DSB.
这些条款所规定的特殊或附加规则与程序同DSU规则是何种关系呢？DSU第1条第2款对该问题作了原则性规定：
Article 1
Coverage and Application
2.The rules and procedures of this Understanding shall apply subject to such special or additional rules and procedures on dispute settlement contained in the covered agreements as are identified in Appendix 2 to this Understanding. To the extent that there is a difference between the rules and procedures of this Understanding and the special or additional rules and procedures set forth in Appendix 2, the special or additional rules and procedures in Appendix 2 shall prevail. In disputes involving rules and procedures under more than one covered agreement, if there is a conflict between special or additional rules and procedures of such agreements under review, and where the parties to the dispute cannot agree on rules and procedures within 20 days of the establishment of the panel, the Chairman of the Dispute Settlement Body provided for in paragraph 1 of Article 2 （referred to in this Understanding as the “DSB”）, in consultation with the parties to the dispute, shall determine the rules and procedures to be followed within 10 days after a request by either Member. The Chairman shall be guided by the principle that special or additional rules and procedures should be used where possible, and the rules and procedures set out in this Understanding should be used to the extent necessary to avoid conflict.
该款规定的原则是，当本谅解的规则和程序与附件2所列的特殊或附加规则和程序存在差异时，应以附件2中的特殊或附加规则和程序为准。对于何为“存在差异”，上诉机构曾经在“危地马拉水泥案中”指出，“只有在DSU中的规定和某个协定的特别或附加程序和规则不能被认为是互补时，特别或附加程序和规则才能优先适用。也就是说，如果它们之间存在冲突时，特别或附加程序和规则才能优先适用。”实践中，专家组或上诉机构总是尽可能的协调和解释、适用它们。特殊或附加规则和程序只是对特定的具体事项的规定，不能取代“谅解”对整个争端解决制度的规定。[1]
在WTO争端解决案件中，一项争议涉及两个以上的协定是很常见的。例如，在“印尼汽车产业案”[2]中，就涉及《补贴与反补贴协定》、《与贸易有关的投资措施协定》和《与贸易有关的知识产权协定》等。如果两个协定都有特殊规定并且相抵触，则当事双方应进行协商，确定适用于本案的规则和程序。如果双方在自专家组设立后20日内达不成协议，则任何一方都可以请求DSB主席确定规则和程序，而DSB主席经与当事方磋商，必须在接到请求后10日内完成这项任务。DSB主席遵循的原则是，尽可能使用特殊或补充规则，而本谅解的规则和程序只应在没有抵触的情况下使用。因此，DSB主席应尽量使用现有规则，而不是另创一套新规则。
（3）附件4中的诸边协定，主要有《民用航空器贸易协定》和《政府采购协定》。[3]另外，1996年新加坡部长级会议上通过的《信息技术产品协定》也属于诸边协定。
二、所适用具体案件的范围
对于WTO争端解决机制的受案范围，GATT 1994第23条规定了三种情况：另一成员违反了协定的义务；另一成员采取了某种未违反协定义务的措施；其他情况。[4]WTO的谅解在第3条第8款和第26条对此问题又进行了更详细的规定。
（一）违反之诉
根据GATT第23条第1款（a）规定，“违反之诉”是指一成员认为其依照协定所享有的直接或间接利益由于另一成员违反协定义务的行为被抵消或减损而提起的诉讼。为了具体界定该问题，在GATT实践中发展出了“初步被抵消或减损的情况”的理论。根据著名WTO学者Jackson教授的研究，该理论主要适用的情况有：（1）违反关贸总协定承担的义务；（2）实行进口数量限制；（3）在某些情况下，通过国内补贴完全排除进口等。[5]
DSU第3条第8款规定：In cases where there is an infringement of the obligations assumed under a covered agreement, the action is considered prima facie to constitute a case of nullification or impairment. This means that there is normally a presumption that a breach of the rules has an adverse impact on other Members parties to that covered agreement, and in such cases, it shall be up to the Member against whom the complaint has been brought to rebut the charge. 该规定意味着，只要“被诉方”违反了协定义务，该行动即被视为初步构成利益抵消或减损的情况，当然“被控方”有权进行反驳。显而易见，根据该规定，WTO争端解决机制DSU所确立的程序无条件地适用于违反之诉。[6]
（二）非违反之诉
根据GATT第23条第1款（b）提起的申诉，通常被称为非违反之诉。具体来说，一成员在他成员“非违反”的情况下提起“诉讼”，必须首先证明自身的利益被抵消或减损。这种规定不仅在法律上，而且在事实上保障成员方利益，确保成员方获得更广泛的权利义务平衡的各种商业机会。但是，由于理论上并未对非违反之诉的范围进行明确的界定，实践中提起非违反之诉是比较容易的，只需证明自己的利益被抵消或减损即可。这样，稍有不慎就可能出现滥用“非违反之诉”的情况。GATT在实践中提出了“合理期望原则”来解决此问题。
合理期望原则是在“智利诉澳大利亚补贴硫酸铵案”中提出的，主要是指如一成员否定了其贸易伙伴可以合理期望获得的利润，则该非违反行为所造成的抵消或减损就可成立。合理期望原则应符合以下条件：（1）投诉方原来产生期望时，不可预见这一被控措施的出现；（2）被诉的措施使投诉方根据已达成的协定、被诉方的言辞或行为而产生的对更好的市场准入条件的合理期望落空。[7]
DSU第26条第1款不仅重申了GATT第23条第1款（b）的规定，而且作了进一步的规定：
Non-Violation Complaints of the Type Described in Paragraph 1（b） of Article ⅩⅩⅢ of GATT 1994
Where the provisions of paragraph 1（b） of Article ⅩⅩⅢ of GATT 1994 are applicable to a covered agreement, a panel or the Appellate Body may only make rulings and recommendations where a party to the dispute considers that any benefit accruing to it directly or indirectly under the relevant covered agreement is being nullified or impaired or the attainment of any objective of that Agreement is being impeded as a result of the application by a Member of any measure, whether or not it conflicts with the provisions of that Agreement. Where and to the extent that such party considers and a panel or the Appellate Body determines that a case concerns a measure that does not conflict with the provisions of a covered agreement to which the provisions of paragraph 1（b） of Article ⅩⅩⅢ of GATT 1994 are applicable, the procedures in this Understanding shall apply, subject to the following:
（a）the complaining party shall present a detailed justification in support of any complaint relating to a measure which does not conflict with the relevant covered agreement;
（b） where a measure has been found to nullify or impair benefits under, or impede the attainment of objectives, of the relevant covered agreement without violation thereof, there is no obligation to withdraw the measure. However, in such cases, the panel or the Appellate Body shall recommend that the Member concerned make a mutually satisfactory adjustment;
（c）notwithstanding the provisions of Article 21, the arbitration provided for in paragraph 3 of Article 21, upon request of either party, may include a determination of the level of benefits which have been nullified or impaired, and may also suggest ways and means of reaching a mutually satisfactory adjustment; such suggestions shall not be binding upon the parties to the dispute;
（d） notwithstanding the provisions of paragraph 1 of Article 22, compensation may be part of a mutually satisfactory adjustment as final settlement of the dispute.
DSU的规定表明了慎用非违反之诉的态度。投诉方应当提供详细的理由，证明被诉方的措施虽然不违反协定，但其根据这些协定应得的利益受到了影响，或者协定目标的实现受到了阻碍，即投诉方负举证责任。被诉方没有义务撤销该措施，专家组或上诉机构应建议有关成员达成一项相互满意的调整方法，补偿可以作为调整的一种方式。经争端一方的要求，可以通过仲裁来决定关于利益被抵消或减损的各项水平，仲裁也可以提出调整方法和手段的建议。
（三）其他情况之诉
GATT/WTO中没有涉及“其他情况之诉”的案例。投诉方只有在认为不存在上述两种诉由时，才能提起“其他情况之诉”。投诉方应当提供详细的理由，说明不存在违反或不违反的情况而自己的应得利益受到了影响，或者协定目标的实现受到了阻碍。如果专家组认为本案还存在着“违反”或“非违反”的事项，则应当作出两份报告：一份向DSB提出，关于这些另外的事项；另一份关于“其他情况之诉”。
[1] 韩立余：《既往不咎——WTO争端解决机制研究》，北京，北京大学出版社，2009，第5页。
[2] WT/DS54/R, WT/DS55/R, WT/DS59/R, WT/DS64/R.
[3] 附件4中的另外两个协定：《国际奶制品协定》和《国际牛肉协定》已于1997年年底终止。
[4] 当然，这三种情况下成员须证明其利益被抵消或减损，或者协定目标的实现受到了阻碍。
[5] 余敏友、左海聪、黄志雄：《WTO争端解决机制概论》，上海，上海人民出版社，2001，第120页。
[6] 姜作利：《中国与WTO争端解决机制——案例分析与对策研究》，济南，山东人民出版社，2007，第9页。
[7] 沈四宝主编：《世界贸易组织法教程》，北京，对外经济贸易大学出版社，2005，第363页。