The invention relates to a disc-shaped cam extrusion type clutch based on magnetorheological liquid. The disc-shaped cam extrusion type clutch consists of an input set, an output set and a piston camset, and the input set comprises an input shaft and an input end shell; the output set comprises an output shaft, an output end shell and an electromagnetic coil; the piston cam set comprises a piston, four cam support rods and four disc-shaped cams; the disc-shaped cams are provided with magnetic conductive ends and non-magnetic conductive ends; and the output shaft and the input shaft are assembled to form an interlayer cavity filled with the magnetorheological liquid, the side, provided with a drainage hole, of the outer circle of the piston communicates with an annular cavity, after the electromagnetic coil is energized, the non-magnetic conductive ends of the disc-shaped cams are affected by magnetic field force to clockwise rotate rightwards by 90 degrees, thus the head of the pistonis extruded to move rightwards, the magnetorheological liquid in the multi-stage interlayer cavity is extruded, the magnetorheological liquid in the interlayer cavity is changed from like liquid intolike solid, and the input shaft drives the output shaft to rotate synchronously through shearing force on the adjacent face of the output shaft and the input shaft. The problems of jitter and impactwhen the automobile clutch transmits the force and torque are solved.