In traditional thyroid surgery, it is difficult for clinicians to effectively determine the position of the recurrent laryngeal nerve by visual recognition. It is prone to recurrent laryngeal nerve injury, which lead to patients unable to speak normally and even endanger lives. Intraoperative nerve monitoring (IONM) techniques is useful for effectively identifying nerve signals and thus avoiding intraoperative nerve injury. This paper introduces the design and implementation of IONM in detail. The system consists of main control module, current stimulation module and EMG acquisition module. The main control module adopts ARM+FPGA dual-core architecture to realize the current stimulation module and signal acquisition module. At the same time, the data collected by the acquisition module is processed. The current stimulation module uses high-precision D/A conversion chip as the core to design the current source circuit, which is used to control the intensity and pulse width; The acquisition module adopts high-precision A/D analog conversion chip as the core and adapts low noise amplifier circuit to realize the acquisition of neural EMG signal. The recurrent laryngeal nerve experiment and clinical experiment were carried out in this system respectively. It is proved that this system has ability effectively to stimulate recurrent laryngeal nerve signal and recognize nerve EMG signal, which meets the needs of clinicians.