Friction clutch capable of implementing forced separation and using method of friction clutch

A friction clutch capable of implementing forced separation comprises a supporting seat, a fixed friction plate, a movable friction plate, an elastic ring, an inner gear ring, an input spline shaft, a piston, a brake pressing opening and a spring, wherein the elastic ring is positioned between the movable friction plate and the fixed friction plate; the fixed friction plate is connected with the inner gear ring through a spline; the movable friction plate is connected with the input spline shaft through a spline; and the elastic ring is used for separating the movable friction plate from the fixed friction plate. The friction clutch can be used in a winch speed reducer, and the movable friction plate is separated from the fixed friction plate by elasticity of the elastic ring, so that quick descending of the speed reducer can be realized.