Each work area of the marine riser has its corresponding specific sea conditions, and the feasibility of macroevaluate is poor. For the feasibility of the whole problem of poor riser assessment, a method was proposed to segment the entire riser calculations, and assessment comprehensively. The marine riser common risk factors were collected to establish risk assessment model, and the gray correlation theory was used to assessment segmented riskof marine riser. According to the major risk factors associated with the risk of occurrence probability, for each segment, the invalidation problem and unreasonable weightswere calculated, the probability of failure of each section of the riser was further calculated by combining the weight with failure correlation coefficient of each section in a variety of major risk factors . This method of risk assessment of the marine riser provides a new way to strengthen the management and maintenance for marine riser of each section.