In the context of the more frequent application of the leniency system for pleading guilty and accepting punishment, the connotations of the rules on victim involvement should be enriched in the 2018 Criminal Procedure Law. Victims deeply influenced by the concept of cooperative justice will also have an intention to cooperate, thus resulting in a rationale for victims\' cooperation. Victims\' cooperation features a subjectivity of interactivity, understanding, and constraint. This kind of cooperation faces the accused, the procuratorial organ, and the court. The jurisprudential function of the rationale for cooperation of victims is embodied in such aspects as recognizing the victims as eligible subjects, enhancing the legal force of the recognizance in a case of pleading guilty and accepting punishment, and consolidating the legitimate basis for victim to obtain legal assistance. Oriented to protecting right of action of the victim, understanding and developing the rationale for the cooperation of the victim can start by reaching a judicial consensus on the “two limits”principle, optimizing the right of action system for victims, achieving the interconnection of multi-level litigation systems, and improving the rules on lenient punishment to enrich the plan for protecting victims\' right of action in cases of pleading guilty and accepting punishment.