In principle, the res judicate of a public interest litigation filed by a consumer group subjectively expands to the parties to the litigation, whist it objectively concerns the judgment in the text of adjudicate. Since a public interest litigation filed by a consumer group tends to maintain public interests by way of a group litigation, the res judicate of such litigation should subjectively expands to consumers whose interests have been prejudiced as well as the organizations and groups which have the right to litigate; the same should also extends to judicatory ground objectively. It is difficult to adapt to actual judicial practice if a theoretical expansion explanation is made only with respect to the res judicate of consumer group public interest litigation. China should perfect its diversified dispute resolution mechanism and consumer group litigation mechanism, all in an effort to narrow the gap between the system design and theoretical explanation and actual needs.