Taking Yanguan Lock in Lianyungang as an example, this paper focuses on the operation environment, maintenance and overhaul of the ship lock’s PLC on the basis of the observation of a shiplock for a year. This paper analyzes and generalizes the maintenance and optimization of electrical components such as the stage recorder and limit switch. It also discusses how to maintain and solve the common breakdowns of shiplock hydraulic and other machines & equipment. Moreover, the paper summarizes the maintenance and overhaul of the automatic control system.