The utility model provides a power end device of a rectangular inspection well system capable of continuously and automatically dredging. The system can move without the need that a person goes down to the well and has a good dredging effect. The power end device of the rectangular inspection well system capable of continuously and automatically dredging comprises a power end device comprising a power end support arranged in an inspection well; the power end support is also glidingly connected with a tension wheel fixing frame; a vertical telescopic oil cylinder is connected between the tension wheel fixing frame and the power end support; a first fixing frame and a second fixing frame are connected onto the power end support; two horizontal telescopic oil cylinders with the opposite telescopic directions are arranged at the bottom of the power end support. The moving of the power end in the horizontal plane is realized by the horizontal telescopic oil cylinders, a trailer circulation device is driven to move in the horizontal plane, the trailer circulation device is driven to move in the vertical plane by the vertical telescopic oil cylinder, a worker does not need to go down to the well in the moving process, labor is saved and the work efficiency is improved.