The harm of nitrogen dioxide is not limited to the great impact on the atmosphere, environmental safety and even harms human, animal, and plant life. Damage to devices and buildings can cause industrial accidents, huge property losses, and even cause casualties. Nitrogen dioxide (NO2) has attracted much attention as a toxic gas with high content, many sources, and greater hazards in the air. In recent years, with the development of industry and the emission of a large amount of automobile exhaust, the emission of nitrogen dioxide has been increasing every year. The air emission in the potential nitrogen dioxide emission area should be treated in time, and the emission must be carried out at a concentration that meets the standard. Only by detecting the concentration of nitrogen dioxide in the emission site at all times can the gas be effectively treated. The inspection system has been designed, it is still inadequate in many aspects. For example, the system takes a bit long time to warm up, and the solder joints are prone to poor contact. In future research, there can be two main research directions: 1. Improve the writing ability of C language to improve the stability of the detection system. 2. Find and synthesize more stable gas-sensitive materials to improve the sensitivity of the signal acquisition system and the accuracy of detection. Although the system has worked accurately and met the requirements, there is still a long way to go for future research, and more in-depth research on the product is needed.