Abstract: To study the nonlinear multi-coupling stiffness effect introduced from the elasticity, flexibility, secondary bending, and clamp constraint of the main cable of suspension bridges during the stiffening girder hoisting construction, taking the precise secant geometry shape of the main cable structure as the analysis object, this paper establishes a composite spring analytical model considering the multi-coupling stiffness effect, based on the constructional physical mechanism and classic analytical theories, which are based on the existing research on each single characteristic. A suspension bridge example with the single main span of 1038 m is introduced as a case. The traditional catenary, beam finite element methods and the proposed method are used to simulate the main cable behaviors during hoisting construction, respectively, in order to investigate the influence laws of the multi-stiffness effect on the main cable internal force and shape, and its variation characteristics under different secondary bending feature coefficients and stiffening girder hoisting sequences. The results show that, in the early hoisting stage, the main cable shape and axial force errors induced by the multi-stiffness effect are more obvious and vary dramatically, and are gradually reduced until being stable in the middle-later stage as the hoisting goes on. For the distribution, the maximal multi-stiffness effect of each stage occurs right at the new loading points, and the maximal positive and negative shape errors during the hoisting construction are basically located at 1/4 span and 1/2 span of the main cable, respectively. The maximum relative error from the conventional beam element and cable element finite element methods both occur at the earlier and later stages of the hoisting construction. The effect increases as the secondary bending feature coefficient increases, and can be more evident when adopting the stiffening girder hoisting sequence from pylon to mid-span. This method and results can provide references for the construction design and monitoring of suspension bridges.