The calibration and error analysis of miniaturized atmosphere CO2 detection system were carried out by Li-7500 analyzer. Firstly, the CO2 volume ratio concentration was calibrated according to the measured data of four days. The absorption degree of the system was linear with the concentration CO2 measured by the Li-7500 CO2 analyzer, and the volume of CO2 was in good agreement with the calibration coefficient of the concentration. Secondly, the system was calibrated by the average data. The absolute value of the relative error of carbon dioxide volume ratio was less than 2.0%, and the correlation coefficient of Li-7500 CO2 analyzer was more than 0.9, which showed the stability and reliability of the system. Finally, according to the influence of temperature change on the atmospheric transport effect, the near ground CO2 in Hefei Science Island was analyzed. The characteristics of the diurnal variation showed that there was a strong negative correlation between the change of CO2 concentration and the change of temperature in the near ground. In summary, the accuracy of calibration results was verified, which provided data support for subsequent measurement of vertical profiles of CO2.