The invention discloses a device for checking whether goods shelf cross beam mounting holes are qualified or not through single light path transmission. The device comprises a base, a conveying belt, a proximity switch, a check block, a pushing air cylinder, a measurement bracket, a portal frame, an image shooting module, a closed shell and a compression air cylinder, the image shooting module comprises a parallel light source, an industrial camera and a reflector set, and parallel light emitted out of the parallel light source sequentially passes through a second mounting hole, a second reflector, a third reflector, a third mounting hole, a fourth reflector, a fifth reflector, a sixth mounting hole, a sixth reflector, a first reflector and a first mounting hole and is cast to the industrial camera. The device is simple and compact in structure and low in production cost, the mounting hole detection process is conducted on line continuously, the production process does not need to be interrupted, production efficiency and detection efficiency are greatly improved, real-time monitoring is conducted through the detection result, the phenomenon of disqualification existing in the production process is effectively avoided, and production quality is improved.