The conventional meteorological data of a hail process happened in Shandong from 23 to 26 May 2008 are used to analyze the synoptic situation, stratification conditions, trigger mechanism of the hail process, and the evolution characteristics of two very similar clouds from primary state to disappearance under catalysis and noncatalysis. It indicates that the hail cloud is intensified to disappear by the hail suppression operation, which is manifested as weakened echo intensity, reduced echo height, decreased VIL and shortened duration. The contrastive analysis of convective clouds in horizontal and longitudinal direction helps to collect 18 samples of hail suppression operation, whose echo intensity and echo height before and after the operation are used to do statistical test. It is found that when the significance level reaches 0.01 and 0.05, the echo intensity is weakened and the top height goes down, and the effect of hail suppression operation is obvious. By using the threedimensional hail cloud numerical model and the seeding amounts, the effect of hail suppression operation is studied, and the hail suppression operation can reduce the hail of about 27%.