《反垄断法》第18条第2款针对纵向价格限制（RPM）规定了竞争损害抗辩规则，垄断协议的违法性认定模式应当据此形成共识，第一层在第17-18条项下衡量反竞争效果和促进竞争效果，明文规定的横向协议不可抗辩地推定具有竞争损害，纵向价格限制可抗辩地推定具有竞争损害；第二层在第20条项下衡量竞争损害与经济效率或公共利益，垄断协议豁免制度具有效率抗辩和公共政策抗辩的双重属性。适用除外制度划定了反垄断法的适用范围，应当与协议豁免制度区分。协议豁免制度包含集体豁免和个案豁免，安全港可分为在禁止条款项下运行的竞争效果推定安全港和在豁免条款项下运行的豁免推定安全港，集体豁免与豁免推定安全港具有同等含义，第18条第3款可解释为豁免推定安全港，该款规定未排除在第20条项下发展出其他豁免推定安全港的制度空间。协议豁免的制度价值在于协调实现反垄断法的多元价值目标，效率抗辩例外矫正了竞争与创新、效率之间的适当性关系，公共政策抗辩则为非经济公共政策在反垄断法中的体现提供了制度接口。引入比例原则作为协议豁免制度的分析框架具有理论和实践层面的可行性，适当性要求限制行为与豁免情形间具有实质因果关系；必要性要求单位有效程度下限制行为对竞争的损害程度最轻；均衡性则在阿列克西重力公式的模型内分析。比例原则的框架具有灵活性，在仅涉及竞争与经济效率的权衡时均衡性可以内含于必要性进行判断。基于经济效率的豁免主要包括研发协议、专业化协议和标准化协议三类情形，认定标准可借鉴欧盟相关经验予以明确。基于间接效率的豁免有时蕴含对促进就业等公共政策的考量，包括有助于中小企业主观经济效率提升的中小企业豁免和避免结构性产能过剩中高效率企业被迫出清的经济不景气豁免。基于公共利益的豁免中，应严格界定公共利益的范畴并适用比例原则的完整分析框架，附带限制法则与我国制度兼容性相对较弱。基于外贸利益的豁免在当前国际贸易格局中具有必要性。关于附加条件，严重限制竞争应从经营者市场份额和相关市场壁垒两方面考察；消费者分享利益则应从商品或服务的价格、质量、种类等多方面考虑限制行为给消费者带来损失的风险与收益确定。

Article 18, Paragraph 2 of the Anti-monopoly Law of the People‘s Republic of China (hereinafter collectively referred to as “the Anti-Monopoly Law”) establishes the anti-competitive defense rule for Resale Price Maintenance, suggesting a consensus formation in the analysis model of monopoly agreements. The first layer involves measuring anti-competitive and pro-competitive effects under Articles 17-18, where typed horizontal agreements are irrefutably presumed to harm competition, while Resale Price Maintenance is defensible presumed to harm competition. The second layer, under Article 20, weighs competitive harm against economic efficiency or public interest. The exemption article of monopoly agreements has dual attributes of efficiency defense and public policy defense. The application of exclusionary system delineates the scope of the Anti-Monopoly Law, distinguishing it from the agreements exemption system which includes block and individual exemption. Safe harbors are divided into competition effect presumption under the prohibition clause and exemption presumption under the exemption clause. Block exemptions and exemption presumption safe harbors are synonymous. Article 18, Paragraph 3, interpretable as an exemption presumption safe harbor, does not preclude the development of other such harbors under Article 20. The value of exemption system of monopoly agreements lies in coordinating the diverse goals of the Anti-Monopoly Law, where the efficiency defense exemption corrects the appropriateness relationship between competition and efficiency, and the public policy defense provides a system interface for non-economic public policies in antitrust law.Introducing proportionality principle as a framework for the exemption system is theoretically and practically feasible. Appropriateness requires a substantial causal relationship between restrictive agreements and exemption scenarios. Necessity demands that the competitive harm should be minimized under a given standard of efficiency promotion. Proportionality in the narrow sense is analyzed within the model of Weight Formula designed by Alexy. The framework of proportionality principle is flexible, allowing proportionality in the narrow sense to be implicitly included in necessity when only competition and economic efficiency are involved. Exemptions based on economic efficiency primarily include R&D, specialization, and standardization agreements, with recognition criteria referencing EU competition law rules. Exemptions based on indirect efficiency sometimes consider public policies like employment, including small and medium-sized undertakings exemptions that aim to subjective economic efficiency and crisis cartels to prevent efficient undertakings from bankruptcy due to structural overcapacity. Public interest-based exemptions should strictly define the category of public interest and apply a complete framework of proportionality principle. And the ancillary restraint doctrine is incompatible with the Anti-Monopoly Law. Exemptions based on foreign trade interest are necessary in the current international trade landscape. Substantial restriction of competition should be examined from both the market share of the undertakings and barriers of the relevant markets. Benefits sharing of consumers should consider the risks and rewards to consumers from the restrictive agreements in terms of price, quality, and variety of goods or services.