•A simple and effective one technique is used for the measurement of the spall strength.•The free surface velocities of the specimen were measured by a laser detector.•The spall strength of granite specimens under static pre-confining pressure is obtained.•Spalling strength decreases with an increase in the static pre-confining pressure. A testing method of spalling strength at different static pre-confining pressure is proposed in this paper. Using a modified split Hopkinson bar facility, a static pre-confining pressure was loaded before dynamic loading. The pull-back method is used to calculate the spalling strength and the free surface velocities of the specimen were measured by a laser detector system. The experimental results indicate that the spalling strength is related to the static pre-confining pressures. When the impact loading and rate effect are almost the same, the results demonstrated that the spalling strength decreases with an increase in the confining pressure.