The utility model discloses an ECU mounting structure of an automobile electric back door. The utility model belongs to the technical field of automobile parts, the utility model discloses an ECU mounting structure of an automobile electric back door. The ECU mounting structure comprises an ECU assembly and a metal plate bracket, eCU assembly comprising a mounting housing, injection molding supporting legs are arranged on the two sides of the mounting shell correspondingly. a metal insert is arranged in the injection molding support leg; the metal insert and the metal plate support are fixedlyconnected through a bolt assembly. The beneficial effects of the utility model are that; the installation structure is simple and convenient to install, the ECU assembly is firmly installed on the metal plate support, the rigidity of an installation point is improved, breakage and scrapping of an outer installation shell of the ECU assembly in the installation fixing process are prevented, heat generated in the working process of the ECU assembly is dissipated in time, and the service life of the ECU assembly is prolonged on the whole.