The temporal information of alarm messages from a faulted power system plays an important role in fault diagnosis，and how to appropriately employ the temporal information for quickly achieving accurate fault diagnosis results of complicated fault scenarios is an important yet unsolved problem.Some research work has been done in this area，but is still very preliminary.In most existing power system fault diagnosis methods with practical application potentials，the temporal information is not well explored.The cause-effect net（CEN）is a graphic-modeling tool for representing the causality between faulted components and operations of protective relays and circuit breakers，and is characterized by rapid reasoning and easy knowledge-base maintenance.Given this background，the CEN is extended to accommodate temporal information and a temporal CEN（TCEN）is then developed.A new method for power system fault diagnosis based on TCEN is proposed.The proposed TCEN based method could not only maintain the advantages，but also improve the fault tolerant capability of the exiting CEN based fault diagnosis method.Moreover，the proposed method could better explain the fault evolution procedure.Finally，an actual power system is served for demonstrating the feasibility and efficiency of the proposed method.