This paper presents the dynamic growth behavior of the voids in ductile metals under dynamic loading condition. Started from energy conservation law, a dynamic damage model on void growth process is developed, in which inertial effect is taken into account. The proposed model on void growth is introduced into Gurson model through VUMAT subroutine, so the void growth behavior affected by inertial effect can be investigated and compared. Numerical analysis shows that inertial effect decreases the rate of void growth, and with the increasing of the loading rate, the decreasing effect becomes more remarkable. Inertial effect is very sensitive to the initial damage of the material and the distribution of the void density. The larger the initial damage and the sparser the void density, the stronger the inertial effect on the void growth.