With the rapid development of long-distance pipeline industry in china, the quality of pipeline insulation materials becomes importantfor oil and gas transportation. because of is advantages as the insulation material, rigid poly urethane foam has been widely used in the long-distance pipelines. however, the current standards for polyurethane foam are different. since there is aslo a lack of systematic study on the impact factors of insulation materials, it is urgent to find out a practical analytical method to determine the major impact factos on the insulation quality. this paper intoduces the grey relational analysis (GRA), uses C# language to program its mathematical model and proposes sush program to analyze the impact factors of rigid polyurethane foam. the application shows that this method is simple, rapid, accurate and practical which makesit suitable for other applications.