Abstract: In order to solve the problems of low degree of intelligence, single function and poor safety of electric control system of domestic horizontal directional drilling rigs, an intelligent electric control system for mine horizontal directional drilling rig is designed. The system is mainly composed of a microprocessor, a voltage and current detection module, a safety barrier acquisition module, a leakage blocking module, a leakage current detection module and a pilot module. The safety barrier acquisition module uses switching safety barriers, analog safety barriers, and thermal resistance safety barriers to limit voltage and current and obtain fault isolation so as to improve the accuracy of signal acquisition and the safety factor in the signal acquisition process. The leakage blocking module adopts the method of applying direct current to detect the equivalent insulation resistance of the motor to ground, and compares the calculated resistance value with the setting value of the leakage blocking action resistance to realize the removal of the motor leakage blocking fault. The leakage current detection module adopts the method of applying a zero-sequence current transformer to detect the leakage current in the circuit online. After the analysis and judgment by the processor, the module achieves the purpose of removing the leakage fault quickly. The pilot module not only realizes the remote control function, but also collects the fault signal on the basis of meeting the requirements of intrinsic safety performance so as to reduce the misoperation effectively. The test results show that the system realizes the basic functions of remote and on-site start-stop control of the motor and remote pilot protection. The current acquisition accuracy is high and the error is less than 2%. The fault identification is accurate and the leakage blocking protection and overload protection actions are accurate and reliable.