The large blocks of ore rocks with a size exceeding 1.2 m generated during the natural caving mining method of Pulang Copper Mine have caused problems of equipment blockage and increased costs. To address these problems, the block size distribution and energy distribution characteristics of secondary crushing for three typical large ore rocks under different numbers of blast holes were analyzed in detail using finite element numerical simulation. Firstly, the block size distribution data of ore rocks were obtained through image processing and field measurement, and the ore rocks were classified. Secondly, finite element software was used to simulate the evolution of blasting stress, crack propagation, and energy dissipation. The results show that the number of blast holes has a significant effect on the crushing efficiency of large ore rocks. With the increase in the number of blast holes, the stress distribution within the rock becomes more uniform, and the crushing effect is enhanced. When the number of blast holes is the same, the three typical large ore rocks are subjected to similar blasting load pressures at the same distance from the blast holes. The blasting load pressure decays rapidly with the increase of the distance from the blast holes. During multi-hole blasting, the stress value on the central line of two-hole distribution is the maximum, while that on the central line of three-hole distribution is the minimum. With the increase in the number of blast holes, the number of cracks correspondingly increases, forming longer cracks or a more extensive crack network in the ore rock. Moreover, multi-hole blasting creates directional cracks or crack zones. After multi-hole blasting, the block size distribution characteristics of the ore rock are uniform and well-crushed. The number of blast holes is directly proportional to the maximum values of kinetic energy and internal energy. Under the condition of the same number of blast holes, the internal energy of ore rocks of various sizes remains stable, and the ratio of kinetic energy to internal energy of the rock decreases with the increase of the size of large ore rocks. Therefore, in the secondary crushing construction of rocks at Pulang Copper Mine, single-hole blasting can be used for small-sized large ore rocks, while double-hole blasting is suitable for medium-sized and large-sized large ore rocks.