Sandcarrier fluid makes sliding sleeve tee erosion and leads to sliding sleeve ball seal failure，and sealing performance of the sliding ball sleeve is one of the key factors which influence the well completion technique of horizontal well fracturing open hole.According to the actual working condition of the sliding ball sleeve，based on fluid mechanics，the cutting deformation theory and the test data，a set of suitable simulation analysis standard and evaluation method for tee erosion was established to research erosion failure of the sliding ball sleeve seal.Based on the above standard and method，fluid software was used to optimize taper tee structure.The results show that maximum erosion wear rate of the tee is mainly distributed in the diameter change area of funnel cone.With the increasing of tee taper,the maximum and average erosion wear rate are also increased accordingly,and present the changing tendency of the quadratic function.