The invention discloses a motor transition connecting device. The motor transition connecting device comprises a connecting disc, a transition disc and a transmitting disc, and the motor the transmitting disc, the transition disc and the connecting disc are sequentially arranged in the axial direction of the motor. The connecting disc and a working element are welded into a whole. The transition disc is connected with the connecting disc through uniformly-distributed bolts. The outer contour of the transmitting disc and the inner contour of the transition disc are both polygonal. The transmitting disc is connected with a motor shaft through a spline. The motor transition connecting device has the beneficial effects that the device has the characteristics of being simple in structure, high in reliability, convenient to maintain and the like, the maintenance cost is greatly reduced, and force transmitting is effectively ensured.