To study the effect of prefabricated hole defects on type I crack propagation and the mechanism of action, a three-point bending dynamic impact experiment was conducted on the Brazilian semi-disk prefabricated with type I edge crack and hole defects by using the digital laser dynamic caustic line method. The result showed that: under impact loading, after being subjected to the impact load, the stress concentration of the prefabricated edge crack tip is higher than that of the prefabricated internal holes, so the internal defects are less sensitive to the impact load. When the crack I growth close to the prefabricated hole, the prefabricated hole would cause the fluctuation of crack growth velocity and stress intensity factor, and the larger the hole, the stronger the influence. When the crack is connected with the prefabricated hole, the passivation effect of the circular hole will inhibit the further development of the crack. After the passivation crack is started again, the crack tip stress intensity factor increases by 124.56%~190.60% compared with the maximum value before the connection, and the growth velocity increases by 47.06%~57.89%.The size of the prefabricated hole has an optimal solution, which has the most obvious inhibition and passivation effect on the re-crack of the crack, and the highest crack initiation toughness. The reason for this phenomenon is the combination of loading rate and specimen defect characteristics.