Abstract: To solve the problems of traditional variable stiffness actuator (VSA), such as heavy structure, limited stiffness adjustment range and high energy consumption, a reconfigurable element multi-winding variable stiffness actuator (ReMWVSA) is proposed. Through dynamic adjustment of elastic element preload and reconstruction of multi-pulley block, active regulation of output stiffness is realized. The theoretical analysis shows that the equivalent stiffness of the system is jointly acted by the elastic element stiffness K₁ and the preload contribution stiffness K₂, and both of them increase significantly with the increase of the number of branch elements N. The test results show that the stiffness regulation range of ReMWVSA is 0-732.29 N·m/rad, the regulation time is only 0.085 s, and the energy storage efficiency is increased by 18%. Compared with the existing VSA, its mass is reduced to 1.7 kg and the volume is reduced to 7.8×10⁵ mm³. At the same time, it has the characteristics of high dynamic response and low energy consumption, providing a new solution for the safe and compliant control of robot joints.