Abstract: As an important form of safety protection for CNC machine tools, gate interlocking function plays a vital role in the protection of machine operators. In order to better meet the safety protection requirements of the machine tools, the gate interlock is used to realize the control function, and the operation process is safe and effective. In this paper, an optimal solution for CNC machine tool gate interlocking of FANUC-OiC/OiD/OiF system is proposed. Based on the basic functions of traditional gate switch and gate interlocking security protection, the optimization of operation scheme and the development of improved functions are completed, and the reliability of safety gate lock is further improved while ensuring better and safe operation. A full range of manufacturers to meet the needs of safety protection.