In order to understand the mechanism of surface erosion caused by the impact of liquid drops on the blade in the turbomachinery,the effects of contact angle,drop diameter and impact velocity on the impact force of a drop colliding with a stationary plate were discussed with the VOF method.The results show that the impact force is slightly affected by the variation in contact angle but considerably influenced by the change in the droplet diameter and impact velocity.Moreover,if the impact force is normalized by the product of the 2.118th power of the droplet diameter and the 1.761th power of the droplet impact velocity,the curves of the normalized forces for drops at different Re and We numbers verse dimensionless time almost all collapse into a single curve,and the normalized peak force occurs at the dimensionless time of 0.26.This indicates that the same size drop at a higher velocity experiences its peak impact force at an earlier time while the impact force of a larger drop at the same velocity reaches its peak at a later time.