Abstract: A micro-gas controller for GC4000 gas chromatograph was developed. The device is equipped with an electromagnetic valve at the inlet end. Through the automatic detection of flow and pressure by the microprocessor and controller, it can achieve quantitative control of air inlet. By controlling the pressure and flow of air inlet, the concentration of gas can be easily and quickly analyzed, which makes GC4000 more accurate and convenient to use. The results of the comparison test between the manual inlet and the micro-gas controller at the inlet end of the gas chromatograph show that the device has good intake stability and accuracy.