Extrusion roller vibration and deflection often appear in the working process of dry granulator controlled by common solenoid valve,which seriously affects the quality of powder forming.The hydraulic system of dry rolling granulator was reformed by electro-hydraulic proportional control technology.By analyzing the force balance equation of extrusion roll bite angle,it was proposed that the friction coefficient between powder material and extrusion roll surface was the main factor affecting the working characteristics of extrusion roll.Combined with AMESim and ADAMS software,a mechanical and hydraulic co-simulation model was built aiming at dry granulator before and after modification.The operating characteristics of dry rolling granulator were compared and analyzed with the variation of friction coefficient.The simulation results show that compared with the operating characteristics of the dry rolling granulator before modification,the pressure of the hydraulic cylinder,the displacement,velocity,acceleration,angular velocity and angular acceleration of the extrusion roll after modification are more stable,and the dynamic friction coefficient between the powder material and the surface of the extrusion roll is increased,which can significantly improve the stability of the dry rolling granulator.