Abstract: Aiming at the problems of blockage of ore-pass transportation in underground mine caused by hanging-up arch, the mechanism of hanging-up phenomena was analyzed. It is considered that the fundamental cause of a hanging-up arch generated in ore-pass is the size of the internal friction between ore and rock particles and the adhesion resistance of fine particles. The following factors play a very important role on hanging-up arch generating, these are the matching relationship between the maximum block size of ore and rock in the ore-pass and the diameter of the ore pass, the content of cohesive powder minerals, the rate of water content of minerals and the size of the diameter of ore pass. Meanwhile, the interlocking force, internal friction and the cohesive force between the coarse and fine particles is enhanced by the action of impact compaction on the surface of material in the orepass when the ore block is falling down and the gravity compaction of material in the orepass. A series of measures on preventing the hanging-up arch generated in ore-pass are proposed from two aspects of the design and the management of ore-pass. It also gives out the common method on the dredging of orepass.