The invention provides a door convenient to detach and install for a transformer substation. The door comprises a door frame, a transom and door leaves. The door frame is composed of an upper frame body, a left frame body and a right frame body. The door frame and a wall are filled with sealing materials. The door leaves are opened oppositely and hinged to the left frame body and the right frame body respectively. Steel channels with horizontal openings are fixed to the left frame body and the right frame body respectively. The transom and the door leaves are connected and fixed through a transom bottom rail inserted in the steel channels. According to the door convenient to detach and install for the transformer substation, the door of a room of the transformer substation can be rapidly and conveniently installed, fixed and detached and the installation and transport efficiency of devices of the transformer substation can be accelerated.