In order to achieve rapid detection of large-span suspension bridges， an improved damage detection method is proposed based on dynamic amplification coefficients. Firstly， the damage index is constructed by comparing the impact factor of intact and damaged bridges， where the baseline data of intact bridges are obtained by a program of vehicle-bridge coupling vibration. Then， the peak value and overall trend of the damage index of the bridge are analyzed to locate the damage and evaluate the damage degree. The effectiveness of the method for bridge damage localization and quantification is verified through numerical simulations and tests on a scaled-down model of suspension bridges. Both numerical simulations and test results show that the method can accurately locate the damage of suspension bridges and realize the quantitative analysis of the damage degree. The difference between the damage index of the damaged bridge and the intact bridge is used to assess the damage of the bridge， which can eliminate the influence of the bridge surface irregularity on the damage identification. This method has strong anti-noise ability and a good prospect of engineering application.