In order to improve the measurement accuracy of cable force of suspenders with connecting rods by vibration frequency method，a calculation of cable force measured by the vibration frequency method based on finite element method is proposed. Considering the errors of fundamental frequency of suspenders caused by the length and stiffness of connecting rods，the influence of cable force calculated by vibration frequency method is analyzed. ABAQUS is used for establishing vibrating models of suspenders with varied length ratio and stiffness ratio between suspenders and connecting rods. Results of finite element analysis are fitted through PYTHON to introduce the adjustment coefficient of cable force. Finally，this method as well as traditional vibration frequency method and method of references 6 are used for calculating the cable force of eight suspenders of Xiaohe Bridge. Results show that this method can effectively reduce the measurement errors of cable force and improve the accuracy of calculation by vibration frequency method.