The invention discloses a multifunctional universal quick coupler, which comprises an upper connecting frame, a swinging device, a rotary speed reducer, a quick coupling device, a hydraulic control valve unit and an electric control system connected with the hydraulic control valve unit. The upper surface of the rotary speed reducer is respectively connected with the upper connecting frame and the hydraulic control valve unit, the lower surface of the rotary speed reducer is connected with the quick coupling device, and the lateral surface is connected with the swinging device. The universal quick coupler can rotate 360 degrees around its own axis and incline left and right at an angle of 40 degrees with respect to the neutral planes of the accessories. At the same time, the quick coupler assists the bucket arm cylinder of the host machine to extend and retract up and down and rotate 120 degrees so as to implement rotary compound motion with three degrees of freedom along three coordinate axes X, Y and Z. Meanwhile, the invention with the function of quickly replacing the accessories expands the work scope of the host machine and has high efficient and convenient operating capacity, thereby implementing the all-round and multi-angle operation of connected accessories and improving the operating efficiency of the host machine greatly.