This study is about the optimal strategy of restoring hand functions of the quadriplegics by functional electrical stimulation (FES). Nowadays, there are many assistive devices developed for restoring the quadriplegics' lost functions by FES. If patients can use their residual capabilities to control these devices, it will be very exciting thing for them. However, the input sources or the command controller are usually complicated or inconvenient for them to use. If there is the optimal strategy of controlling built, the quadriplegics will benefit much from it. In this study, we had designed the optimal strategy of the patient-driven command controller for restoring their lost hand functions by FES. The proposed optimal control strategy can also be modified and applied for different rehabilitation applications.