Abstract: In order to analyze the wear rate and reliability of cementing sliding sleeve after high discharge,high sand-fluid ratio and long-term erosion of solid-liquid flow,downhole tools’ erosion and wear were researched based on the erosion theory and numerical simulation.The effects of the number of ports,sand concentration and displacement on the wear rate were analyzed.New test equipment was designed and built to test the erosion wear of port collar of cementing sliding sleeve under certain working conditions.A new model of erosion rate was established and more research was conducted about the flow capacity of port collar of cementing sliding sleeve and its effect on the rate of erosion wear.By combining numerical analysis and test data,the erosion coefficient of cementing sliding sleeve made by type A material was obtained.Results showed that the hole erosion was more severe when the cementing sliding sleeve contains two holes.The erosion rate had a linear relationship with sand concentration and an exponential relationship with fluid displacement.This research provided theoretical basis and foundation for cementing sliding sleeve reliability evaluation and guide for sliding sleeve application in oilfield.