Abstract: The current reliability analysis method of long-distance natural gas pipeline is mainly depending on experts'opinions. The accuracy of the evaluated probability of pipeline event would be easily affected by the variance and subjectivity from experts' opinions. In this paper, the establishment of credibility model based on D-S evidence theory is introduced. By this model, various judgments from different experts on reliability of natural gas pipeline can be treated according to the credibility. The deviation from the reliability analysis caused by the one-sidedness in knowledge and subjectivity of experts can be solved, and the accuracy of the analysis result can be improved. As some shortages still exist in the D-S evidence theory, unified standard should be constituted to achieve the consistency of fuzzy language and fuzzy number and improve the accuracy of pipeline reliability analysis.