Abstract: In order to propose a comprehensive corrosion risk evaluation model based on an analysis of the corrosion risk of sea water pipe systems of ships in service, the modes of potential corrosion and their causes were first analyzed by identifying the origins of the inner and outer corrosion of the sea water pipe systems. In accordance with the matrixes of corrosion occurrence possibility and corrosion risk consequence, a corrosion risk matrix was established for a sea water pipe system. The method for the quantitative evaluation value of each mode of corrosion possibly occurring in a sea water pipe system was then presented. The comprehensive evaluation model of the corrosion was first built using the Analytical Hierarchy Process(AHP), which can be used for the comprehensive corrosion evaluation. The results show that the comprehensive evaluation value will be expressed as the corrosion risk level and corrosion-induced consequence of the sea water pipe system. This will be very useful for accurately protecting the sea water pipe systems of ships in service from corrosion, thereby attaining the goals of economy, rationality and timeliness.