In this paper, a scheme of single-motor driven multi-joints lower limb exoskeleton based on controllable clamper is proposed in order to reduce the number of driving motors, overall weight and structural complexity of the lower limb exoskeleton. We propose a new type of tendon-sheath artificial muscle as the transmission method for exoskeleton according to the Hill muscle model. A controllable clamper is used to control the contraction and relaxation of the artificial muscle, and a pair of series and parallel springs is used to imitate the characteristics of the muscle. On this basis, we designed the mechanical structure of the system, and figure out the relationship between assistant force and driving motor’s angle, then planned the control timing sequence of the clampers. The driving motor’s angle curve is determined by theoretical calculation. A platform is built, and the experimental results verify that the scheme of single motor to drive multi-joints is feasible and effective.