Abstract: In order to avoid blocking of holes and gaps of the pressure screen in the process of screening waste paper pulp screening, the fluid characteristics such as viscosity of the waste paper pulp with different concentrations were first tested and analyzed; and then the flow field inside pressure screen was drawn with Unigraphics NX software(UG)finally,pulp suspension flow field inside the pressure screen was simulated with computational fluid dynamics(ICEM CFD)and FLUENT software. From the numerical simulation,the detail distribution of the pressure,turbulence intensity and velocity of pulp flow in the screening zone were obtained. The results for the pressure screen used with representative pulp and structure’s characteristics and running parameters showed that the highest turbulence intensity near the corrugated plate was 306% and highest turbulence intensity in the screen holes was 128%; the maximum velocity at the screening holes’ inlet was 8.16 m/s,the maximum velocity at the screening holes’ outlet was 3.5 m/s,and the average was 1.2 m/s; and the biggest static pressure near the screen plate at the head of rotor wing was about 1.8×10⁵ Pa and the minimum static pressure at the end of rotor wing was 6.92×10⁴ Pa.