In order to investigate the appropriate stemming length of borehole in blasting and the propagation law of stress wave in the borehole,theoretical analysis and numerical simulation were used to analyze the mechanism of the borehole stemming mechanism.On the basis of the basic hypothesis,a calculation model of the stemming length was established by studying the stemming dynamics and compression deformation of the stemming.Furthermore,the rationality of this model was verified.To simulate the explosion stress nephogram of the single hole and dynamic response curve at the bottom of the blasthole and free face of the blasthole with a stemming length of 0.35 m when rectangular coupling charge at the bottom of the continuously coupled hole,a mechanical model with a regional size of 1.5 m×1.5 m,a hole depth of 0.62 m and a hole diameter of 0.04 m was established by using the finite element analysis software.The results show that the stress wave propagates outward in the form of spherical wave,and the stress appears first in the center area of the blasthole charge and reaches the maximum.The stress wave is finally released after reflection and superposition.Especially,the stress at the bottom of the hole reaches its peak rapidly in a very short time,then oscillates up and down,and gradually stabilizes at a certain value.It is a very short period of time for the stress wave caused by the explosion that reaches the free face.However,the stress on the free face reaches the peak value quickly,and then decreases rapidly until the stress wave is released completely.This method can provide reference for the analysis of blasthole stemming and be applied in blasting analysis of coal mine blasting face.