The embodiment of the invention provides a vehicle-mounted lifting system. The vehicle-mounted lifting system comprises a fixing device, a sliding frame, a locking mechanism seat, a working platform,an adjusting rod, a first fixed pulley set and a movable pulley set. The fixing device is connected with a vehicle chassis; the sliding frame is placed on the fixing device through a sliding part; thelocking mechanism seat is arranged at one end of the fixing device and used for locking one end of the sliding frame at one end of the fixing device; the first mounting position of the working platform is connected with the other end of the sliding frame; one end of the adjusting rod is connected with the second mounting position of the working platform, and the other end of the adjusting rod isconnected with the other end of the fixing device; the first fixed pulley set is mounted at one end of the fixing device; and the movable pulley set is mounted on a guide rail of the fixing device andconnected with the first fixed pulley set through a first stretching part.