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 (R_s) was measured by 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 R_s during winter wheat bloom-growth period.In 2018-2019 growing season, compared to CK, C₁₂₀ treatment significantly increased R_s 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;while in 2017-2018 growing season, compared to CK, C₈₀ treatment had no significant effect on R_s.A positive exponential relationship was found between soil respiration rate and soil temperature.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 of 120 μmol·mol^-1 increased CAC during the growing season of winter wheat.