An auxiliary drive assembly for wheelchairs is revealed. The auxiliary drive assembly includes a wired transmission member, at least one sensor, a control circuit and a drive unit. The wired transmission member is arranged at a wheel hub on a wheel. The sensor is set on the wheel for generating a sensing signal sent to the wired transmission member. The control circuit is coupled to the wired transmission member, receiving the sensing signal and generating a control signal. The drive unit is coupled to the control circuit and receiving the control signal so as to drive the wheel hub rotating and further move the wheel. Thereby the assembly is with simple structure and the environmental interference is minimized by wired signal transmission. The sensing signal is sent to the control circuit exactly and the drive unit is controlled to rotate the wheel precisely. The wired transmission reduces the cost.