To study the effects of the confining pressure (Cp) on the mechanical properties and damage evolution of deep rock masses under multiple impact loading, the improved split-Hopkinson pressure bar was used to perform cyclic impact on granite samples with Cp = 0, 4, 8, 12, and 16 MPa. The experimental results indicated that the total number of impacts increased with the increase in Cp. The sample with Cp = 0 MPa was destroyed with only one impact and exhibited a typical type-I stress–strain curve. The samples with Cp = 4, 8, 12, and 16 MPa exhibited typical type-II stress–strain curves. Under the same cyclic impact loading, a higher Cp yielded a lower rate of increase of the average strain rate and maximum strain, as well as a lower rate of decrease of the peak stress and elastic modulus. The peak stress and maximum strain exhibited a good negative linear correlation and positive linear correlation with the average strain rate, respectively. At Cp = 4 and 8 MPa, the cumulative damage of the sample gradually increased with the increase in the number of impacts. At Cp = 12 and 16 MPa, the compaction effect caused the cumulative damage to be negative in the first few impacts. Subsequently, the cumulative damage gradually increased owing to the impact damage-softening effect. Additionally, the sample with Cp = 0 MPa was pulverized, and the fragmentation was severe. At Cp = 4, 8, 12, and 16 MPa, the Cps inhibited the free expansion of internal cracks in the sample, and the sample exhibited a significant shear failure mode with less fragmentation.