The compressive failure of ceramics is always accompanied by an explosive fragmentation process that creates lots of fragments flying away at high speed. Due to experimental limitations, the details of compressive fragmentation occurred inside the specimen are not clear. In this paper, the compression crushing process of alumina ceramics was numerically reproduced by discrete element method. The size distribution of fragments under different strain rates, the average splash velocity of fragments and the variation law of fragment velocity in different areas within the specimen were analyzed. The simulation results show that as follow: (1) Both the compressive strength of ceramics and the average splash velocity of fragments increase with the increase of loading strain rate. (2) The dispersion velocity of debris is related to its initial position. The dispersion velocity of peripheral debris is the largest. With the decrease of distance between initial position and central axis of the specimen, the dispersion velocity of debris decreases gradually. (3) With the increase of loading strain rate, the number of fragments produced by fragmentation increases gradually, and the corresponding average size of fragments decreases. The energy conservation and conversion mode in the compression crushing process of the specimen were further discussed, and the average velocity of debris splashing was theoretically analyzed.