A direct numerical simulation for threedimensional gas-solid two-phase wake flow of a non-uniform inflow has been carried out.For gas-phase flow field

a highly accurate and compact finite difference method is used to solve directly the N-S equations.For calculating the particles' field

Langrangian approach is used to trace the motion of particles with stocks number to be equal to 1.Particle collison with wall surface is simulated by using elastic collison method.Under condition of non-uniform inflow(Re=260)

the influence of disturbance upon flow field characteristics and upon particles' diffusion has been analysed.Results of simulation show that the disturbance at inlet accelerates the formation of big vortex

increasing disorder of the fluid

and enhancing the diffusion degree of particles in the fluid.