Abstarct: In this project the goal is to design and build a leg movement simulator mechanism for testing the orthopedic implants. For this purpose, first, the leg movement and gait cycle were studied, and the motion characteristics were extracted. Then, using some design constraint, a mechanism was designed to simulate leg movement in the gait cycle. In designing the mechanism, to stimulate the mechanism of two DOF with only one motor, the idea of using a curved-shaped groove has been used. After the design, the mechanism was simulated in سالیدورکs software. Also, for force analysis, the mechanism was transferred to Adams software, and the results of force analysis were extracted. Adams's results show that the designed mechanism is very close to what was intended to simulate the leg movement. Finally, an experimental model of the mechanism was built, and its operation was investigated.