Prefabricated GRC composite component

The utility model discloses a prefabricated GRC composite component which comprises a wall body, a component body, a drainage channel and a downpipe, the component body is detachably installed on one side of the wall body, and a fastening bolt is detachably installed in the middle of the top of a connecting block; the component body and the adjusting block on the front face of the wall body can be rapidly positioned through the connecting block on the back face and the inserting groove, the adjusting block can adjust the suitable distance through sliding, rapid installation matched with the connecting block is facilitated, and the problems that when an existing component body is installed, inserting blocks are oppositely inserted, inserting holes need to be reserved, and an external supporting structure needs to be installed are solved. The connecting blocks can be stably installed on the tops of the inserting grooves through fastening bolts, stable connection of the component body and the wall body is achiev