The analytic hierarchy process is introduced to construct energy efficiency index system of gathering and transportation system, which provides a favorable means for energy efficiency evaluation of the system as a whole. Combining with the triangular fuzzy number in fuzzy theory, the judgment matrix construction and weight calculation of AHP are reformed. To some extent, it reduces the defects of hierarchical analysis, such as the strong subjective factors of legal person and the neglect of the model of people's cognition of objective things, and makes the evaluation results more accurate and comprehensiv. Taking a gathering and transportation block of oilfield as an example, the weakness of its energy consumption is found out, and the improvement suggestions are put forward.