Abstract: In order to determine the reasonable starting point combination of the millisecond blasting in the 24 m high step hole of Barun mine, the nonlinear dynamic analysis software ANSYS/LS-DYNA is used to make the hole according to the millisecond blasting mechanism under the condition of the conventional high step blasting parameters.The numerical simulation and comparison analysis of the time series of different detonation points in the inner differential blasting are carried out.It is concluded that the combination of the differential detonation stress field law and the in-hole differential detonation sequence in the high step blasthole is the lower low-end first detonation, the upper part, the top delay interval has the best detonation effect.