Abstract: There are some problems existing in the importance analysis of influencing factors in crude oil pipeline flow safety evaluation. Considering the actual fluctuation of such influencing factors, this paper proposes a new method for importance analysis. According to the actual probability distribution of influencing factors during the stable operation of pipeline, a new measurement standard of importance is defined to facilitate the prioritization of influencing factors by importance. In this paper, the results of importance analysis and sensitivity analysis on actual influencing factors for inlet temperature of a pipeline are compared. The result shows that the new method for importance analysis can combine the practical operation condition of pipeline with actual fluctuation of influencing factors, so as to reflect the impacts of different values of influencing factors and different fluctuation ranges on importance. This new method can be used to effectively and comprehensively analyze the importance of influencing factors.