In view of crushing magnetite ore in metal mining enterprises, engineering problems exist such as huge energy consumption and low energy utilization ratio. Split Hopkinson pressure bar device and high-speed photography technology were utilized in this study. First, the pattern and mechanism of energy migration and transformation of magnetite ore under impact load were studied. Second, the standard square hole sand and stone sieve and the GZS-1 high frequency vibrating sieve were adopted to investigate the fragmentation distribution of magnetite ore, the variation of the average particle size, and the transformation process of ore impact crushing mode under different dissipation energy. Then, the correlation problem between ore energy dissipation rate and crushing degree was analyzed with the increase of strain rate. Finally, combining with the basic factors that affect ore fragmentation distribution, the prediction model expression of the average particle size of magnetite ore was derived. The research shows that with the increase of incident energy, the decrease of ore wave impedance changed the transmission coefficient and the reflection coefficient between ore and pressure bar, and affected the distribution of each energy in incident energy. It means that the energy dissipation rate and the energy reflectance increased, but the energy transmittance decreased. The higher the dissipated energy was, the severer the degree of ore broken was. When ore dissipated energy is increased from 14.79 J to 121.18 J, the main distribution region of ore fragment size moved from the coarse-grained end (26.5 mm, 37.5 mm) to the fine-grained end (4 mm, 16 mm). There was a subtractive logarithmic relation between dissipated energy and average particle size (d_s), and d_s reduced by nearly 56.04 %. There was a critical value in d_s. When d_s was greater than this value, there was a positive correlation between energy dissipatation rate and crushing degree. Conversely, there was a negative correlation between them. At this value, the magnetite ore could be broken optimally. The results have certain reference value for the control of energy consumption in the crushing process of magnetite ore.