In order to accurately simulate the position of the saddle in the analysis and calculation of a suspension bridge, and then obtain the accurate shape of the datum strand in the construction site, this paper puts forward a calculation method on the position of the saddle and the geometric shape of the datum strand on the basis of considering the friction between the main cable and the saddle. Firstly, the calculation method of friction between the main cable and cable saddle is proposed and the formula of the deviation between the coordinates of the initial position and that of the equilibrium position of the cable saddle is derived. Then, through theoretical derivation, the calculation program of cable geometric shape considering the change in saddle tangent point is compiled. Combined with the analytical algorithm, the concept of temperature telescopic bar is introduced, and a simulation method of the cable saddle and datum strand is given, which is suitable for the combination of finite element analysis and numerical algorithm. Finally, the reliability of the algorithm is verified by the comparison of a numerical example, and by changing the value of friction, the influence of friction on the saddle position and the datum strand geometric shape is analyzed.