Abstract: As a fine reaming method in through hole, industrial robot is designed to eliminate the defects inside and outside the hole and improve the accuracy of robot hole making. However, due to the stiffness defects of the robot, the mode coupling chatter related to the intrinsic modes is easy to occur during milling and reaming. Aiming at solving the problem of effective signals extraction of mode coupling chatter in the process of milling and reaming of industrial robots, a method based on EEMD (ensemble empirical mode decomposition) and BPF (band-pass filtering) was proposed in this paper. The eigenmodes with mode coupling chatter frequency as the excitation frequency were determined by EEMD, and the unilateral trend discrimination was introduced to improve the efficiency of extreme value calculation in EEMD. By selecting the energy entropy ratio and correlation coefficient, and combining with BPF, the mode coupling chatter information in the intrinsic mode was extracted, and finally the mode coupling chatter signal was reconstructed. Experimental results showed that EEMD has a certain mode aliasing inhibition effect compared with EMD. The experimental result of spindle speed 1 800 r/min and radial cutting thickness 0.6 mm showed that EEMD-BPF is 0.31 s ahead of EMD-BPF in detecting chatter.