The fragmentation of rock induced by impact loading is one of typical nonlinear problems in underground engineering rock specimen such as rock plate was found to become invalid under impact loading. This paper presents brittle fragmentation for dynamic damage of rock plate based on the edge-on impact (EOM test with vary impact velocity (10 ms- to 40 ms-) and impact angle and describes and explains this dynamic weakness phenomenon. High-speed camera was used to study the relation among crack initiation and propagation, impact velocity and impact angle. The results demonstrate that only a damaged zone appeared on the edge of the sample when the impact velocity is less than a critical value, its size increased with the increase of the impact velocity：when the velocity exceeds the critical value, some radial cracks occur around the damaged zone and extend outward from the boundaries of damaged zone. The radial crack length and damaged zone increase with impact velocity and are influenced by the impact angle. However, at a certain velocity, suddenly, the damage zone decreases and the crack length increases, it shows that there was an obvious incubation period of crack forming. According to test results, the study found that the impact velocity of this jump is about 25 ms-130 ms-1 and the scope of impact resistance optimized angle is about 150-300.