In the past various methods to restore motor functions in persons with spinal cord injury (SCI) have been developed. Functional electrical stimulation (FES) methods and wearable power assist suits with actuators have been proposed in the areas of medical sciences and engineering respectively. However, complete restoration of motor functions in persons with SCI has still not been successful. In this paper we made the musculo-skeltal model, which is the bipedal walking model with a new hybrid power assist orthosis with FES and actuators. And we examined safety and control method of orthosis by simulating gait of persons with SCI with the developed model.