Abstract: It was carried out an analysis of fatigue performance of crane girder using FE simulation according to the result of fatigue performance stress testing of crane girder for a steel plant. The result indicate that stress concentration is obvious on the mutation section of the crane girder and fatigue performance is serious. With the advances in production technology, the cranes are increasing the frequency of operation which will make the under-load effect coefficient increase significantly. The value in the existing Code of Design of Steel Structures (GB 500172003) may be is lower than that of the actual situation, leading to insecurity. Therefore, it was recommended that 0.9 should be taken as the value of under-load effect coefficient for the heavy duty work system of crane hook in order to ensure the fatigue security of crane girders.