This paper presents a method for flutter derivatives ident ification of bridges based on HilbertHuang transform(HHT). Accord ing to the theory of HHT, firstly, the measured acceleration response signals of free vibration for a sectional model in a wind tunnel experiment are decomposed into a series of intrinsic mode function (IMF) components by the empirical mode decompo sition (EMD) and HHT is applied to the IMF components which ha ve the largest amplitudes to obtain the corresponding instantaneous amplitudes a nd instantaneous frequencies．Ａccordingly，the natural frequencies and the modal damping ratios are determined by signal processing. Secondly, the complex mode shapes are obtained by the fitting of the free vibration responses in time domain. Finally, the eight flutter derivatives are identified by solving the structural state equation. Simulation results show the good noiseresistance and reliability of the m ethod. The wind tunnel experiment validates the feasibility and practicality of the method.