Abstract: The causes of an explosion accident caused by detonator explosives were comprehensively investigated, and the methods of personnel inquiry, on-site verification, equipment verification and laboratory test were fully integrated for analysis. Finally, it is confirmed that the reason for the accident is that the blasting worker had contact with the fluorescent lamp cable and signal cable suspended on the side of the lane at the narrow place, and the outer cover of the cable rubber sleeve and the inner insulation layer of two core cables are damaged during passing through, which leads to the exposure of the one of the charged core wires to contact with the metal conductive body outside the basket and form the current path and cause the electric detonator explosion in the basket. This accident was caused by a series of factors including illegal transportation, illegal placement and cable explosion, etc. To avoid the recurrence of similar accidents, lessons should be learned and alarms should be sounded.