The invention discloses a multichannel change-over valve which comprises a valve body, a valve body end cover, a rotary cam and a drive motor. The valve body is arranged on the valve body end cover, and a concave hole D for allowing the rotary cam to be mounted and a valve body bearing hole for fixing the rotary cam are formed in the inner side face of the valve body. A plurality of extruding shrinkage pipe mounting holes and a plurality of guide grooves C are formed in the valve body in the circumferential direction of the rotary cam; a counter bore G for allowing the drive motor to be mounted is formed in the position, at one side of the valve body, of the valve body end cover, and a concave hole E and a concave hole F for allowing a driving gear and a driven gear to be mounted respectively are formed in the back face; the rotary cam is connected with the driven gear, and the driven gear is in engaged connection with the driving gear; a groove B and a groove A are formed in the circumferential direction of the rotary cam; an on-off position disc and an optoelectronic switch are arranged above the rotary cam. The multichannel change-over valve is compact in structure and reliable in work, the manufacturing cost is effectively reduced, the functions that multiple channels are communicated in sequence and communicated at the same time are achieved, the service life is longer, and operation is easy and convenient.