Low concentration gas detection is a hot issue in gas detection. Hydrogen, as a combustible gas and diatomic molecule, has always been the focus of gas detection research. However, in the current detection methods, gas chromatography technology can be used for quantitative analysis or even trace detection, but the test system is complex and expensive; hydrogen electrode detection technology can be used for continuous in-situ detection, but the test range is large and the accuracy is not high; oxidation titration technology is easy to be detected The effect of reducing substances, such as oxygen, has a large error. In order to solve these problems, this paper uses NDIR technology to analyze the key factors that affect the precision measurement of hydrogen concentration detection, and optimizes the design. A high-precision hydrogen concentration measurement and control system is completed. Through experiments, the standard concentration of 2.54%, 6.35%, 8.00%, 11.25%, 20.00% sample gas is tested, and the absolute error of detection is controlled at 0.1 %In the following, the high-precision detection of low concentration hydrogen is realized. After long-term operation monitoring, the experimental equipment has good stability, which verifies the correctness and effectiveness of the improved design.