A position bi-core control method was proposed based on high efficiency of direct drive volume control (DDVC) hydraulic system and high accuracy of hydraulic valve control servo system.The 1st core control was a closed loop valve servo control system,which was composed of digital control valve with stepper motor,actuator,and their mechanical feedback mechanism.The 1st core achieved accurate position control.The 2nd core control was that servo synchronous motor drove piston pump.During 1st core large position error control zone,2nd core system ran in high efficiency by the way that servo motor speed and related piston pump flow were controlled based on stepper motor speed chart,which was determined by actuator accelerating and decelerating capacity,actuator displacement,and difference between initial position and final position.During 1st core small position error servo control,servo motor and piston pump would be stopped when accumulator pressure got the set point.This could avoid pump to run in low speed and low efficiency zone.The stored energy in accumulators would help position servo control.So,2nd core can let system run in high efficiency based on 1st core situations.Bi-core control method has two concise mechanisms and targets.It is practicable and reliable.