Abstract: Steel-anchor-box structure is used in the connection between cable and girder of Shanghai Yangtze River Bridge. Due to large quantities of plates being used in this structure, complex configuration and severe stress concentration, the fatigue behavior of the steel-anchor-box subjected to service live loads need a careful investigation. Full scale test model which can represent the mechanical behavior of anchor-zone is obtained by finite element method, and fatigue testing method is introduced. Combining the traffic condition and the design quantity of variable vehicles, referring the foreign code and relative research, the fatigue load range for the test is determined by the theory of cumulative damage in fatigue, and the calculation shows the light rail loadings is the major causes of fatigue effects in cable-stayed bridge burdened the vehicle loadings and light rail loadings on same layer. Based on the theoretical analysis and the result obtained from fatigue test, resistance fatigue behavior of steel-anchor-box structure in the connection of cable-girder subjected to cycle loading is studied. The results show the cable-girder anchorage of Shanghai Yangtze River Bridge is safe enough.