Obtaining modal parameters of a cutting system is essential for conducting dynamic simulation of milling process. The experimental modal analysis technology (EMA) is used for hammering test on a machine-tool system or a machine-workpiece system, excitation and response signals are measured and acquired by force transducer and piezoelectric accelerometer respectively; Then, the frequency response function of the system is obtained by Fourier transform and the frequency response function estimation method; Lastly, the modal parameters of the system are identified through orthogonal polynomial fitting method. The analysis result of dynamic characteristic parameters can provide necessary reliable data for dynamic simulation of milling process.