An electric power rail fixing device comprises a U-shaped frame. The bottom wall of the U-shaped frame is a vertically arranged flat plate. Two sides of the flat plate are respectively and fixedly provided with a rim. A locating rod is arranged on the two rims, and the locating rod is arranged on the two rims horizontally in a penetrating mode. The outer ends of the two rims are respectively provided with a U-shaped clamping ring, and a locking rod is arranged on the two U-shaped clamping rings horizontally. Active infrared intrusion detector switches are arranged on ring bodies of the U-shaped clamping rings. The electric power rail fixing device is designed directing at the current situation that an existing electric power rail is disordered in management. On one hand, the locking rod is used for blocking a rail out-moving port in the locating rod, and on the other hand, the locking rod is used for controlling the active infrared intrusion detector switches. When the locking rod is displaced, the active infrared intrusion detector switches emit control signals to realize wireless alarming, and therefore the purpose of monitoring a rail in real time is achieved.