Abstract: In order to analyze the process of multi-joint roof failure and stress redistribution, the mining face model is established by 3DEC, the instability mechanism and the distribution law of the bearing pressure and the joint normal stress are analyzed and simulated in the mining process. The simulation results show that: the failure of the multi-joint roof is caused by the failure of the block three-hinged arch structure along the joint surface; due to the presence of lateral squeezing force, only the hinge at the joints will be cracking; comparing with the more complete rock, the heaving phenomenon of multi-joint floor is more obvious; before the first occurrence of the roof, the appearance of the maximum bearing pressure is farther and farther from the working face with the advancing of the working face, the maximum and minimum joint normal stress is basically the same relative to the distance of working face; the normal stress of the joint surface reflects the degree of mutual squeezing between the blocks, which is greater than the bearing pressure.