Carbon dioxide (CO2) is one of the important components of greenhouse gases. Real-time detection of its concentration changes is of great significance for alleviating the greenhouse effect. Non-dispersion infrared (NDIR) method has the advantages of good stability, fast response and wide measurement range. It is widely used in portable gas detection and other fields. Firstly, the advantages of NDIR method in CO2 detection are analyzed, and the principle of NDIR detection is briefly summarized. Then, the basic structure of the NDIR gas analyzer is described in detail. The classical gas calibration methods of the measurement system are summarized. Finally, the characteristics of NDIR are comprehensively analyzed, and the future development trend is prospected.