The existing hydraulic system uses proportional valve or servo valve to control the position of hydraulic cylinder, resulting in very large throttling loss. In order to improve the hydraulic system energy efficiency, a hydraulic electric hybrid linear drive system adopting electro-mechanical linear actuator and hydraulic cylinder was proposed. In order to suppress the coupling effect between the electro-mechanical linear actuator and hydraulic cylinder, the hydraulic pump and the proportional valve were used to control the output force and operation direction of the hydraulic cylinder to meet the load force requirement of the system. The electro-mechanical linear actuator was used to control the operation position of the load. Meanwhile, in the electric motor current control loop of the electro-mechanical linear actuator, the hydraulic cylinder output force fluctuation and external interference force can be compensated. In order to realize the above target, an adaptive sliding mode control method based on extended state observer was designed for the electro-mechanical linear actuator. Based on the load force estimated by the extended state observer, the hydraulic cylinder output force can be openloop controlled by adjusting the pressure of the hydraulic pump and the opening of the proportional valve. In the proposed system, the function of the proportional valve was controlling the move direction of the hydraulic cylinder most of the time. Thus, the throttling loss can be greatly reduced. The operation performance and the energy efficiency characteristics of the hydraulicelectric hybrid driving system were analyzed through simulation and test. The results showed that the proposed system had good position control performance and high energy efficiency. Compared with the traditional valve controlled system, the proposed system’s energy consumption can be reduced by 51%.