The "overtime service" of environmental standards reflects the serious disconnection between current environmental standards and the objective reality of environmental management, this phenomenon has become the direct cause of leading the "sunset clause" into the environmental standards system. As a kind of legal elimination mechanism, the basic idea of the "sunset clause" fits nicely the inherent property of environmental standards. It can balance the conflict between stability and flexibility of law, strengthen the predictability of environmental standards revision and increase the legitimacy of the revision procedure of environmental standards to set the "sunset clause" in the environmental standards system. Only by confirming the period of "sunset" and the validity of period expiration, perfecting the post evaluation system and the program specification of environmental standards revision, and constructing the routine mechanism of environmental standards review and revision, can it achieve the unity of purpose identification and regularity identification of the environmental standards system.