To effectively evaluate the loss of axial force for the bolts in cable clamp of suspension bridge, the influence factors analyses and application of ultrasonic identification method for cable clamp blot axial force in suspension bridge were carried out. Firstly, the axial force calculation formula was established based on the acoustic elastic effect, and the accuracy of this formula was verified by experiments. Then, effects of the non-stress acoustic time difference and stress coefficient difference on the recognition accuracy was analyzed. Finally, this method was utilized to identify the tension efficiency and the axial force loss during the lifting process. The results show that, 1) The acoustoelastic effect of bolts is obvious and the recognition error of screw axial force is less than 1.1%. 2) Identification errors caused by the coupling state of sensors and the blot geometry and material parameters are 47.7 kN and 43.1 kN, respectively. 3) The stress coefficients of different bolts are different. Identification deviation caused by the difference of stress coefficients between calibrated bolts and tested bolts is 4.75%. 4) With the increase of screw nut tightening degree, the tension efficiency can reach more than 94%, which is 95.93% higher than that before the tightening degree of nut is not controlled. The bolt axial force is seriously lost with the increase of beam weight. The measured minimum average axial force of cable clamps is 424.32 kN, which is only 56.58% of the designed axial force. In the process of beam section hoisting, the cable clamp bolts should be tensioned in time to ensure construction safety.