For fault handling of PLC control system in automatic baggage sorting system of Chongqing Airport, this paper describes the important function of PLC in baggage sorting system and the current situation of present PLC control system in baggage system, summaries three fault types in the process of baggage operation, briefly analyzes the reasons for the faults respectively, further proposes a kind of fault checking and tracing system based on faults, in detail illustrates fault diagnosis of PLC key devices such as power module, input/output module, network communication module and so on, summaries practical fault treatment methods and forms fault checking and tracing system.