Winch parking brake

The invention relates to a winch parking brake, and belongs to the technical field of brakes. The problems that an existing brake for a winch is single in braking torque, the braking torque cannot be changed in the later period, the design accuracy of the brake is low, and the overall size is large, so that the product applicability is poor are solved. The device comprises a shell, a rotating shaft and a piston; the rotating shaft is rotationally mounted in an inner hole of the shell; the piston sleeves the rotating shaft and is slidably mounted in an inner hole of the shell; brake discs with inner circles connected with the rotating shaft are distributed at one end, close to the piston, of the rotating shaft, and friction plates forming friction pairs with the brake discs are arranged in an inner hole of the shell; a friction group with at least two friction pairs is formed between the friction plate and the brake disc; and a spring group is pressed between the piston and the inner hole of the shell, pushes