The hydraulic system of dry granulator is mostly controlled by common solenoid valve,even if the electro-hydraulic proportional valve is used,the closed-loop control is not formed.In view of the above problems,the hydraulic system of the 200-type dry granulator was improved and designed based on the electro-hydraulic proportional technology.According to the chatter mechanics model of the extruding roller,the vertical motion differential equation of the roller was deduced.The influence of different extrusion forming pressure on the operating characteristics of the extruding roller was studied by using AMESim and ADAMS to build a mechanical and hydraulic co-simulation model.The results show that the operating characteristics of the extruding roller are stable,and the influence of the extrusion pressure on the displacement characteristics can be neglected.At the moment of system starting up,the peak values of the speed and acceleration fluctuation of the extruding roller reach the maximum,and their fluctuation characteristics can be effectively improved by increasing the extrusion forming pressure.The influence of extrusion pressure on angular acceleration is greater than that on angular velocity.