An inspection device for subway tunnel based on three-dimensional laser scanning includes a three-dimensional laser scanner, an adaptive structure of a track trolley, a power control module for the track trolley, a photoelectric sensor and a body of the track trolley. The power control module is arranged on the body. A support rod is vertically arranged on the power control module, and the three-dimensional laser scanner is mounted at a top of the support rod. The adaptive structure is symmetrically arranged at two sides of the body of the track trolley, and the photoelectric sensor is arranged in the body of the track trolley. The inspection device is designed to be modular, which is convenient to carry and repair, and easy to mount. In addition, the inspection device has low labor cost due to less manual intervention, and the inspection efficiency can be improved.