We estimated the lift and thrust of the proto-wings of the dinosaur Caudipteryx, a close relative of birds, using both theoretical and experimental approaches. Our experiments utilized a newly reconstructed flapping wing mechanism, based on evidence from fossil specimens of Caudipteryx and driven by a DC motor. To ensure that this reconstructed mechanism adequately simulated realistic flapping movements, we investigated the relationships among the flapping angle, twisting angle, and stretching angle of the wing mechanism. We also used two sensors to measure the lift and thrust forces generated by the flapping movements of the reconstructed wing. Our experiment indicated that the lift and thrust forces produced by the wings were small, but increased at higher flapping frequencies. This work not only contributes to current understanding of the origin of avian flight, but should usefully inform the ongoing development of bionic flapping robots.