Abstract: Aiming at the pipelines under traffic loads, this paper thought the invalidation of the pipelines under traffic loads as a fuzzy thing. After the non-smooth characteristic of the traffic loads is taken into account, this paper calculates the fatigue life of the pipelines under traffic loads based on the fuzzy theory and the reasonable choice of the membership function. And the analysis method of the reliability is applied in the calculation. This paper puts forward a simply calculation method in the end. So an explicit analysis way is brought forward for the reliability design on the pipelines system under the traffic loads.