The utility model relates to a switch cabinet bus connecting device, which is composed of a box body and a transitional bus arranged in the box body, wherein the box body is composed of a left box body, a right box body and a transitional box body, the left box body and the right box body are respectively fixed to the top parts of a left switch cabinet and a right switch cabinet respectively, the left box body is communicated with the right box body through the transitional box body, the left box body, the right box body and the transitional box body form a sealed cavity in an enclosing mode, one end of the transitional bus in the box body is connected with a bus end extended out of the left switch cabinet in the phase sequence, and the other end of the transitional bus is connected with a bus end extended out of the right switch cabinet in the reverse sequence. Because of implementation of the technical scheme, the switch cabinet bus connecting device is reasonable and compact in structure, reverse connection between the two switch cabinets is realized through changing the spatial structure of the transitional bus, the insulation effect is good, and the assembly structure of the box body also brings great convenience to inspection and maintenance of the whole switch cabinet bus connecting device.