Using self made drop hammer impact test device, the effect of steel fiber on the impact resistance of concrete was investigated by analyzing the toughness and ductility ratio. The uniformity of the distribution of steel fiber was characterized by fiber dispersion coefficient. Besides, the fractures of the impact surface were observed and the fiber distribution of the impact section was calculated to analyze the toughening mechanism and crack impact resistance properties of steel fiber reinforced concrete. Results show that the addition of steel fiber could increase the impact performance effectively. The ductility ratio is more than 15% when the steel fiber content(by volume) is 08%. The toughness coefficient increases with the increase of the fiber volume fraction. When the steel fiber content is 10%, the toughness reaches the maximum value, which is close to 10 times of the standard concrete. The addition of steel fiber could decrease the brittleness of the matrix and improve its plasticity, which delays the crack development, and changes the shape and the number of main cracks as well. Both of the amount of steel fiber and its distribution on the impact section are closely related to the impact toughness of concrete.