A rehabilitation system with stiffness measurement on a body part to be rehabilitated is disclosed. The rehabilitation system includes a rehabilitation unit and a processing unit. The rehabilitation unit includes an exoskeleton brace holding a rehabilitation part of user and traction lines driving the exoskeleton brace for moving. When the exoskeleton brace moves, the processing unit analyzes tensions of the traction lines to obtain stiffness information relating to the rehabilitation part of user.本發明揭露一種具有測量待復健肢體僵硬程度的功能之復健系統。復健系統包含復健單元與處理單元。復健單元包含結合於使用者復健部位的外骨骼支架與驅動外骨骼支架的牽引線。當外骨骼支架活動時,處理單元藉由分析牽引線上的張力得出使用者復健部位的僵硬程度資訊。