To examine the effects of gradual increase of atmospheric CO2 concentration on soil respiration of winter wheat (Triticum aestivum) field, a gradually increased CO2 concentration experiment was conducted with automatic control system of CO2 in open top chambers (OTCs) during 2017?2019 growing seasons. In this study, a gradual increase of atmospheric CO2 concentration (C80 and C120, an increase of 40 μmol·mol?1 year by year from 2016) was set up based on the ambient atmospheric CO2 concentration (CK). The soil respiration rate (Rs) was measured by the static chamber?gas chromatograph method. The results showed that gradually increased CO2 did not alter the seasonal patterns of soil respiration, but had significant effect on Rs during winter wheat bloom?growth period. In 2018?2019 growing season, compared to CK, C120 treatment significantly increased Rs by 50.2% (P=0.008) at the heading?flowering stage, and significantly increased cumulative amount of CO2 emissions (CAC) by 25.9% (P=0.044) during the wheat growing season, but in 2017?2018 growing season, compared to CK, C80 treatment had no significant effect on Rs. Soil respiration showed a positive exponential and negative linear correlation with the soil temperature and soil moisture, respectively. Compared to CK, gradually increased CO2 concentration reduced the temperature sensitivity coefficient of soil respiration (Q10 values). In summary, a gradual increase of atmospheric CO2 concentration to 120 μmol·mol?1 increased CAC during the growing season of winter wheat.