C4 photosynthesis and photorespiration studies are research hotspot in plant science. However, lacking low CO2 concentration culture conditions and related mutant resources limit the in-depth development of related work. This study designed a low CO2concentration incubator which can stably control plant growth conditions including light, CO2 concentrations and temperature. Test data can be simultaneously update onto the remote website, which made people conveniently to check the experimental records. By using the platform, 54 EMS (Ethyl methane sulfonate) mutants of foxtail millet were grown and screened under 40 PPM (concentration units: parts per million. The range of CO2 concentration is 380-400 ppm in normal air condition) CO2 concentration. According to the number of survival seedlings at death point, these materials can be divided into four types. Among them, 19 mutants at level III and 13 mutants at level IV, were sensitive to CO2 stress. There are also 5 mutants of vein variation which were hypersensitive to low CO2 concentration. Those results confirmed the practicability of employing low concentration of CO2 incubator in C4 photosynthesis-related mutants screening. It could also promote the in-depth study of kranz anatomical structures observation and relevant gene cloning. In addition, the low concentration of CO2 incubator can also be applied to physiology research on photosynthesis and respiration in other main crops.