For a reasonable parameters choice of liveline insulators washing, and improving the cleaning efficiency, the volume of fluid (VOF) model provided by fluid simulation software FLUENT was used, and the simulation research of water washing of insulator subumbrella at different flushing angle and different stress has carried on. The distribution of pressure and velocity of insulator subumbrella, and the law of changes of effective cleaning area with different pressure were analyzed. The results show that increasing the nozzle inlet pressure is helpful to improve the effective cleaning area, but there has a critical value. With the higher flushing angle, the clear mechanism is more direct and effective and can remove higher adhesion strength contamination. When reaching the contaminations critical washing pressure, chosen a lower flushing angle leads to a higher cleaning efficiency. The result of research has provided a useful reference to choose reasonable parameters of liveline insulators subumbrella washing.