The SimMechanics of Matlab toolbox is used to build the simulation model of humanoid robot mechanism. According to the model diagram, the humanoid robot dynamic walking process was observed intuitively, and the angular acceleration of robot body center of gravity and torque variation map of hip joint were solved. A planner five-bar mechanism motion model simulating to the instantaneous state of humanoid robot was established, based on Kane method to solve the dynamic equation of the mechanism. The SimMechanics simulation tools are applied in the mechanism analysis, which provides a convenient and simple method for the mechanical system simulation.