The eligibility of evaluation subjects is a fundamental legal issue for the credit evaluation system of enterprise environmental protection.The existing regulations stipulate that the main body of enterprise environmental protection credit evaluation is the ecological environment department,and there have always been doubts in theory and practice about whether the ecological environment department is qualified as the main body of evaluation,but the existing achievements are limited to basic judgments,and there is still a lack of logical and self-consistent legal evidence.It is difficult to characterize the evaluation behavior carried out by the ecological environment department as the evaluation subject in the administrative law,and the existing theories of non-compulsory administrative means,non-administrative licensing approval,and administrative confirmation cannot explain the qualitative issues of the evaluation of administrative acts by the ecological environment department.As the subject of environmental credit evaluation,the third-party institution has a legitimate source of evaluation rights,that is,the evaluation rights of the third party have a clear source of social interest demand,and also have an epistemological basis for the source of rights.The shift of the main body of enterprise environmental protection credit evaluation from the ecological environment department to the third-party evaluation agency solves the problem of misalignment of power-right allocation in enterprise environmental protection credit evaluation activities,and properly clarifies the appropriate boundary between the exercise of government power and market power.The guarantee norms for the eligibility of environmental credit evaluation subjects should be carried out from the aspects of configuring rights and obligations,improving supervision systems,and strengthening responsibility norms.