Abstract: In the paper, explicit finite element method, three-dimensional Tsai-Wu failure criterion and material stiffness criteria for conversion were used to simulate the impact damage process of the rectangular laminates T300/QY8911, and to predict the extend of impact damage. According to the standards of ‘the general technical specifications of HB 72242—1995 composite structures’ and ‘the general specification of GJB 28952—1997 carbon fiber composite laminates’, the impact specimens were designed, and low-energy impact experiments were carried out. The ultrasonic C scan was used to detect the damages of different impact energy, and compared with the results of finite element method. It showed that the results of finite element simulation were consistent with those of the ultrasonic C scan test on the size of damage areas. Three-dimensional Tsai-Wu failure criterion for damage and material stiffness criteria for conversion were also proved by the experiment results, When the energy reached more than 4.5 J, the delamination of impact damage could be detected by the ultrasonic C scan testing.