A method of milling chatter recognition by change of the power spectrum energy ratio in process of monitoring and processing is proposed.This objective is acheived by measuring the milling force and vibration signals under several cutting conditions.Experimental results show that main character of the power spectrum of signals when chatter happen,corresponding chatter frequency occurs evenly sapacing on both sides of the spindle rotation frequency,cutting frequency and their harmonics.On condition that the power value of the dominant chatter frequency is beyond a certain threshold,chatter occured,otherwise no chatter happened.According to the analytical model for regenerative chatter established and the experimental data obtained in the study,the frequeney response function and cutting force coefficient,based on which the stability curve is drawn.Combined with the method of chatter recognition,accuracy of dynamics model is verified,and can provide reference for slection of reasonable processing parameters and vibration monitoring in actual processing.