Abstract: The present invention provides an auxiliary wheel frame structure of motorcycle, which comprises a wheel frame, a block plate, and a wheel-frame controller. In the auxiliary wheel frame structure, the wheel-frame controller and the wheel frame are assembled to a chassis of a motorcycle. When the wheel-frame controller detects low-speed cruising of the motorcycle, the wheel-frame controller controls the wheel frame to descend. By using a first wheel and a second wheel of the wheel frame, the motorcycle still can be kept stable under low-speed cruising and hence improving riding safety for riders.