Ore crushing is one of the most important steps in mine engineering, and numerical simulation is a useful way to predict the crushing effect under impact load. Based on continuum discontinuum element method (CDEM), by introducing the linear elastic constitutive law into the element and the cohesive model into the virtual interface, the iron ore crushing simulation under different impact velocities was realized. The 2D single circular iron ore mesh and nine circular iron ores mesh with the diameter 3cm were established, the fracture and fragmentation process of iron ores under different impact velocities was simulated, and the evolution laws of fracture degree, damage degree, and the grading curve of fragments were obtained. The results show that, with the increase of impact velocity, the fragments of iron ores increase gradually; The bottom ore is crushed most seriously, while the top ore is damaged lightest, which demonstrates that the lower iron ores have an obvious buffering effect on the upper ores. In the single iron ore impacting case, when the impact velocity increases from 25m/s to 150m/s, the median particle size D50 decreases from 14.7mm to 2.2mm, the fracture degree increases from 1.6% to 28.9%, and the damage degree increased from 5.6% to 43.3%. In the nine iron ore impacting case, when the impact velocity increases from 50m/s to 150m/s, the fracture degree increases from 6.0% to 31.0%, the damage degree increases from 12.3% to 45.4%. When the impact velocity is 100m/s, the median particle size D50 at bottom, middle ant top part is 1mm, 3.6mm and 14.7mm, respectively. The above conclusions can provide basis for optimal design of impact crushing process of iron ore.