In the process of reaming while drilling,the erosion of the reamer ball seat is serious,especially near the bypass hole of ball seat.Based on erosion and solid-liquid two-phase flow theory,erosion simulation analysis were carried out combining DPM discrete phase model,and the influence of different factors on reamer ball seat erosion was studied.In addition,the orthogonal test method was used to study the influence degree of each parameter on erosion wear and optimize the structure of reamer ball seat.According to the analysis of range and variance,the factors affecting the erosion wear of the ball seat are flow>sand content ratio>particle diameter.The optimal process parameter combination is:flow is 35 L/s,sand ratio is 3%,viscosity is 0.028 Pa·s,particle diameter is 0.25 mm and particle density is 1 500 kg/m3,the erosion rate of the ball seat is the minimum,which is 4.52×10-6kg/(m2·s).In order to reduce the erosion of reamer ball seat,the structure of the ball seat was optimized.After optimization,the bypass hole angle of the ball seat is 45° clockwise,the fillet radius is 7 mm,and the number is 6,the erosion rate of the ball seat reduces by 24% compared with that before optimization.