Abstract: The fourth Jianghan bridge is a prestressed concrete cable-stayed bridge with single pylon, double cable faces. Its structural response such as displacement and stress in beam and pylon, tension in cable on the bridge under dead loads, vehicle load and temperature action during its construction and service stages has been measured. The geometric nonlinear behavior of the bridge is studied in this paper. Comparing with linear analysis, the nonlinear results are found to be in very good agreement with the measured data. The results show that the nonlinear characteristics of the bridge are so pronounced that they should not be neglected in the structural response analysis.