In the field test of open-air step blasting, the explosion time is short and there is certain danger, so it is difficult to realize the detailed observation of blasting process. Based on the engineering background of step blasting in a mine, the discrete element model of particle flow is established. Combined with software LS-DYNA and PFC, the throwing and stacking process of step blasting is simulated based on continuous-discontinuous blasting model. Due to the different effects of blast stress wave and blast gas in the blasting process, the blast stress wave and blast gas are respectively simulated in the form of velocity and pressure in the numerical simulation, and the development and distribution of rock cracks in the blasting process and the throwing and stacking effect of blast heap are analyzed. Through field blasting experiments, it is verified that the simulation results are consistent with the field blasting results.