This paper proposes a progressive fault diagnosis expert system based on recorded fault data.It is composed of two parts:substation system diagnoses the fault reason and fault phase,then upload the brief report to the mater station system which integrates several substation reports,diagnoses the fault deeply and gives an analysis of the operation of protection system and related equipment.The system gains fault information by the recorded fault waves?SOE and protector events,adopts the CLIPS based fault diagnosis expert system engine,so it can diagnose the fault accurately and quickly and relieve the burden of operators.