The Central Pattern Generator (CPG) model of a flexor and an extensor was developed, according to the experiments implemented in a crankrotation task. The drive torque, which achieves the arm movement, was obtained by six muscles models consisted of outputs of the CPG model. The parameters of CPG model was optimized by minimum torquechange criterion and genetic algorithm. Finally, the simulation results were compared with the experimental data, and the CPG model of six muscles were discussed.