Referring to the standard API 581 and considering the field environmental situation as well as the relevant corrosion mechanism of pressure vessels, a quantitative analysis method has been proposed to analyze and calculate the damage coefficient of various type, failure probability and failure consequence for pressure vessels. The risk levels of the pressure vessels may be differentiated as several grades, in accordance with the established risk acceptance criteria. Therewith, a proper plant related with schedule, content and measures of inspection, as well as, the relevant control of risk consequences may be formulated for high-risk vessels and components. The research results can be beneficial to the accurate and quantitative evaluation of the risk degree of pressure vessels, and the confirmation of relevant inspection plant for risks. The proposed method is of great significance to the reasonable allocation of human and financial resources for the on-site inspection and the safe production control of platforms. In conclusion, this method has been successfully applied to FPSO in the China sea and may further be adopted as a reference for other projects.

Keywords： API 581 standard ; pressure vessel ; risk ; inspection