Understanding the effects of elevated atmospheric CO₂ on soil respiration is crucial for predicting the greenhouse gas emission in the future. A field experiment was conducted to study the effects of elevated CO₂ on soil respiration of spring maize under three atmospheric conditions (treatments):natural atmospheric conditions with the current CO₂ concentration (marked as CK), open-top chamber (OTC) system with the current atmospheric CO₂ concentration (as the contrast, marked as OTC), and OTC system with elevated CO₂ concentration of 700 μmol/mol (marked as OTC+CO₂). Soil respiration, soil temperature and moisture were measured at the main growth stages of spring maize including pre-sowing (V0), jointing stage (V6), ninth-leaf stage (V9), silking stage (R1), milk stage (R3), dent stage (R5), and physiological maturity stage (R6). The results showed that, compared with CK, OTC+CO₂ enhanced soil respiration rates by 43% and 104% (P<0.05), respectively, at the R3 and R5 stage. Compared with OTC, OTC+CO₂ increased soil respiration rates by 63% and 109% (P<0.05) at the R3 and R5 stage, respectively. There was no significant difference in soil respiration between OTC and CK during the whole growth period of spring maize. The changing dynamics of soil temperature with growth period for the three treatments were consistent, also soil moisture changing dynamics with growth period under the three atmospheric conditions were similar. Soil respiration showed an exponential and parabolic correlation with the soil temperature and soil moisture, respectively. In conclusion, the effects of elevated CO₂ on soil respiration varied with growth stage. Soil temperature and soil moisture were the main factors affecting soil respiration, the elevated CO₂ decreased the temperature effect value (Q₁₀), and increased the threshold value of soil respiration to soil moisture.