To enhance the surgical quality of bone milling surgery robots, it is required that the robot can perceive and control the milling state in real-time, (primarily including milling depth and milling angle). To address this problem, this article proposes a method to utilize a binaural microphone system to assist in milling state control. Firstly, the relationship between the milling state and the acoustic signal is modeled. Then the calibration experiments of milling depth and milling angle are completed to obtain the parameters of the proposed model. Finally the PD controller is used to control the milling state of the robot in real-time by combining it with the established model function. The experimental results show that when the desired depth of milling is 0. 5 mm, the experiment with angle control improved by 7. 0% in terms of milling depth deviation from the desired value and 34. 1% in terms of milling stability compared to the experimental results without angle control. It proves that in the extreme case of the desired depth of 0. 8 mm, the addition of angle control also has the positive effect of improving the milling effect. After experiments, it evaluates that the proposed method can effectively improve the work quality of the bone milling surgical robot.