In order to study the effect of particle size on the erosion of high pressure turbine blade of gas turbine,the CFXTASC flow software was used to simulate the particle trajectory and the erosion area based on DPM (Discrete Phase Model),and Lagrange method was used to track and predict the trajectories of a large number of particles in the flow field.The simulation and prediction of the blade erosion was carried out with the airport runway particles(the particle diameter is from 10 μm to 1 500 μm) at different particle concentration,and the data and images of erosion was extracted by using CFDPost.The results show that the particles at diameter from 10 μm to 80 μm tend to follow the movement of airflow,which causes slight wear of blade;while the locus of coarse grained at diameter more than 100 μm is significantly deviated from the airflow path,which causes multiple serious damage to blade.With the increase of runway particle concentration,the erosion of turbine blade is increased linearly.When the runway particle concentration is 600 mg/m3,the erosion of the leading edge of the blade and the rear leaf basin is most serious,and the average particle erosion rate is 26 mg/g,which is accordance with that of the experimental result in reference.