Abstract: The distribution of blasting fragmentation in open pit coal mines is an important factor influencing the efficiency of resource mining. To clarify the distribution characteristics of coal rock mass under blasting, we use a Split Hopkinson Pressure Bar (SHPB) test system to perform specimen failure test under impact load, and use direct sieving method to analyze the distribution and fractal dimension characteristics of sample damage. Taking the blasting of coal seam in Haerwusu Open-pit Coal Mine as an example, we obtain block distribution information after blasting by image recognition method, and analyze its fragmentation distribution and fractal dimension characteristics. Through indoor testing and production field data analysis, the results show that: as the impact load increases, the average particle size of the sample gradually decreases, and the average particle size change rate gradually becomes smaller; the coal seam damage is more and more severe in the area closer to the blast hole, and the smaller the blasting block.