After studying the working principle of the typical pressure roller mills main working principle, buffering process for the hydraulic system was analyzed in theory, and the simulation model was built in AMESim. The relationship between the accumulators inflation pressure and the systems holding pressure & the pistons displacement was mainly analyzed, and the influence of the change in materials thickness on the systems holding pressure & the pistons displacement was analyzed. The result shows that with higher accumulators volume, the smaller pressure fluctuation of the hydraulic pressure, when the volume of the accumulator is up to 30 L, theres no obvious improvement of the buffering; the diameter of the pipeline is positively correlated with the effect of buffering, the diameter of the pipeline should better be more than 18 mm; the bigger of the accumulators air inflation pressure, the better of the capacity of the systems holding pressure, but higher air inflation pressure will results in the obvious vibration of the piston; the increase of the materials thickness will result in the increase of both the vibration amplitude of the piston & the hydraulic cylinders peak pressure.