Abstract: The hazards of geological disasters affect pipeline construction and operation directly. In this paper, synthetic judgement is made on the hazards of geological disaster of the example gas pipeline section from Zhongxian to Honghuatao with the fuzzy and synthetic judging method in accordance to blurring mathematical principle. Effective in solving the problems of blurring judgement with the characteristics of forthright calculation and good practicability, the fuzzy and synthetic judging method is applicable for evaluating the hazards of geological disasters of various pipelines and areas and construction thereof.