Marine power generator plays important role to guarantee the normal operation of all subsystems of FPSO, in which cooling device are emphasized on its reliability and stability. As the main cooling system of FPSO power generator, the design of central cooling water system is very important. Traditional pipeline network system design is mainly based on the design manual and empirical formula, which single pipeline is designed for circulation of different media. Lacking the concept of system integrity, which results in the weak integrated design without rational consideration. In this paper, a FPSO central cooling water system is taken as the research object. Based on the initial design scheme, it is different from the empirical and singularity of traditional design, and the impact of the pipe network of cooling water system to that of other systems in the whole vessel is put into consideration on the comprehensive way. From the economic point of view, the study on the pipe network of flow balance is carried out, and the optimization scheme of the central cooling water pipe network system is proposed.