To analyze the deformation of main cable of a suspension bridge accurately, changes in the deformation of main cable shape and force action on tower in the construction were analyzed based on the principle of multi-span catenary of main cable. Action of tower on cable saddle was simulated as a nonlinear spring with a beam-column effect considered in calculation of tower stiffness. Two formulas were derived both for nonlinear thrusting rigidity and moment of tower bottom. Based on the free state of main cable, the construction of cable strands for a suspension bridge with a main span of 1280 m ...