Shock experiments on rocks are made with one - stage light- gas gun, and ultrasonic tests are conducted on the damaged rocks. Combining the results of ultrasonic tests with microcosmic observation, the shock - induced damage properties of rocks and the relation between the variation rate of ultrasonic velocity and damage degree can be known. The results indicate that the variation of ultrasonic velocity can reflect the damage degree of rock well, and the damage properties of rock can provide basis for the design of rock blast.