Abstract: By applying Germany's two-stage theory to the construction of green certificates, the entire lifecycle management of green certificates can be divided into two distinct legal relationships. The first stage—covering registration and issuance—possesses public law characteristics such as administrative licensing and administrative confirmation. The second stage, involving trading and cancellation of green certificates, exhibits a hybrid nature primarily governed by private law but also incorporating elements of public authority intervention. The dividing point between these two stages lies in the completion of certificate issuance. The uniqueness of this two-stage framework lies in the involvement of public authority in the second stage: on one hand, public power intervenes extensively during the trading phase through rule-making and market supervision; on the other hand, the cancellation phase incorporates administrative confirmation, transforming the second stage into a model combining "civil contract" with "administrative action." By analyzing the legitimacy, legality, and extent of public authority intervention in the green certificate market, this paper proposes relevant recommendations for improvement.