The cable tray is divided into a trough type, a tray type, a ladder type, a net format and the like, and is composed of a bracket, a support arm and a mounting attachment. The bridge inside the building can be erected independently, or it can be attached to various building (structure) and pipe brackets. It should be characterized by simple structure, beautiful appearance, flexible configuration and convenient maintenance. All parts need to be galvanized. , installed in the open-air bridge outside the building.