Abstract: Because of the present problems such as complex mechanical rolling shear mechanism with crankshaft connecting rod,heavy weight of device and high cost,a composite rod shear with the PR-8R-PR Ⅱ-level groups driven by hydraulic cylinder was designed.Through the establishment of composite linkage position loop equation,moment balance equation,hydraulic control system model,the locus curve of component and the displacement of hydraulic driver element,the parameters of dual-chamber balance force and the transfer function of hydraulic control system,were calculated.Theoretical and experimental results show that the hydraulic servo control system model can meet the feature requirements of recapitulation rolling track of linkage,and the structure design of such mechanism and its comprehensive analytical data are feasible.Meanwhile,the hydraulic servo control system has strong robustness and self-adaptability,which can achieve higher compensation precision under complex and harsh conditions,and the method of asymmetrically-controlled valve to control asymmetrically-controlled cylinder can effectively solve the reversing impact of the shear mechanism to drive hydraulic cylinder.