The overall architecture of the central control system on a 300,000 DWT floating production storage and offloading (FPSO) unit of Petrobras has been taken as the starting point, focusing on the configuration, shutdown logic, main functions and characteristics of its emergency shutdown (ESD) system. According to the safety design rules for the offshore production installation unit of Petrobras, a set of causal logic of safety shutdown system suitable for large FPSO units in the Brazilian sea has been creatively developed on the basis of setting the safety shutdown level and the fire and gas zoning. Combing with the systems of the whole ship and the field production and operation practices, the causes of shutdown should be considered as thoroughly as possible, with clear fire and gas voting logic. The equipment and systems that need to be cut off in the shutdown results at all levels are described one by one, introducing the concept of damper zoning for the first time. The major purpose of the fire and gas shutdown and the emergency shutdown is to minimize the impact of shutdown results on the topside process of the FPSO, and to maximize the safety of personnel and the continuous production. The characteristics of this shutdown method different from the design of traditional FPSO ESD system are summarized at the end.