The invention relates to an installation mechanism of a flexible thin film assembly of a roof photovoltaic power station. The installation mechanism comprises main foot stools and columns, the lower end of each foot stool is provided with an opening, a motor is mounted outside the foot stools, the left end of the motor is connected with a linked gear set, a rotor is fixed in the left end of the linked gear set, hydraulic cylinders are mounted in the internal front and back ends of the main foot stools respectively, hydraulic rods are arranged under the hydraulic cylinders respectively, connection blocks are fixed to the lower ends of the hydraulic rods respectively, and bearings are installed under the connection blocks respectively. The installation mechanism has the advantages that the linked gear set drives the rotor to rotate due to work of the motor, further, a drum rotates, and the flexible thin film assembly is wound around the rotating drum; and operation is very convenient, and a rotating shaft provides reasonable condition for rotation of the rotor.