Abstract: The present disclosure provides a method for testing an internal force increment of an arch bridge suspender by inertial measurement, including the following steps: (1) selecting a suspender to be tested with internal force increment, and mounting an acceleration sensing device or a speed sensing device at a lower edge of the suspender to be tested; (2) setting an appropriate sampling frequency and collecting signals; (3) processing information data collected in step (2) by using Formulas; and (4) recording a result of the information data processing and obtaining the internal force increment of the suspender. The method can obtain the internal force increment of the suspender by collecting acceleration or speed signals of the lower edge of the suspender and performing calculation from the signals. This method has the advantages of simple and convenient testing, high replicability and low test cost.