A remote control system is designed to achieve the stable and economical operation of far-infrared laser interferometer on the EAST Machine (Experimental Advanced Superconducting Tokamak). Based on the PLC controller, the system is set up as two parts: gas flow control for adjusting working gas, feedback control for stabilizing output power of the laser. We demonstrate the feasibility that, according to the need of experiment, the working gas ratio mode can be changed in order to save gas (CD 4 ) instead of keeping a single-mode ratio. Meanwhile, the changes of the output power and power supply of the laser have been measured due to the mode conversion. The output power of the DCN laser, as a laser source, is influenced by a number of parameters, especially the gas ratio and a variety of disturbances. Therefore, the feedback control system has been developed to make the laser power stable near the maximum available power. The whole system has been applied to the DCN laser, and has been proved to be effective.