Abstract: UM-BUS is a high-speed, high-reliability serial bus with dynamic reconfigurable ability. In this paper, we present a three-stage lanes health detection method. In this method, we build a health status table of lanes to implement online and real-time detecting and dynamically marking upon a lane failure. Using this method of dynamic reconfiguration, the communication data can be allocated in the healthy lanes dynamically to transmit. Thus, the normal communication in the case of lane failure can be achieved. Through the testing in the practical UM-BUS system and computer simulation, we illustrate the feasibility of this fault detection method, which can detect various fault of lanes and nodes and meet the application requirements of UM-BUS system.