In order to verify the expansion performance of rotary folding wing, one kind of small rotary folding wing scheme driven by pendulum rod was studied. The expansion equation of motion of the ideal model was derived by applying Lagrange equation of theoretical mechanics; the location of hinge point was analyzed by numerical solution through MATLAB; using the multi-body system dynamics theory, the virtual prototype of the scheme was established in ADAMS, and the kinetic law of motion was simulated. The simulation results show that the motion laws of the small rotating folded wings obtained by the two methods are the same. In full-load case, the expansion time of the scheme meets the design requirements.