Abstract: Based on the comprehensive analysis of long-distance pipeline risk assessment index system, this paper evaluates the pipeline risk indexes by combining gray theory with hierarchy analysis process. Oil and gas pipeline quantitative evaluation model based on gray analytic hierarchy method is established, the range of indexes weight is worked out by using analysis hierarchy process, which together with expert grading, are used to evaluate pipeline risks. This method has been applied to Panjin Oil Pipeline (Shuguang Initial Station-Dongguo Valve Chamber), and the result shows that the third-party interferer is the most serious risk, followed by corrosion, while natural disasters and defects in pipeline itself are relatively safer factors. Gray analytic hierarchy method with both advantages of gray theory and analytic hierarchy process, can not only give zoom analysis of risk factors, but also deal with the weights of every factor more flexibly, making the evaluation modeland process more consistent with objective law, and the evaluation result more accurate and reliable.