A field study was conducted to compare soil CO₂ efflux and CO₂ concentration between mulched and non-mulched cotton fields by using closed chamber method and diffusion chamber technique. Soil CO₂ efflux and CO₂ concentration exhibited a similar seasonal pattern, decreasing from July to October. Mulched field had a lower soil CO₂ efflux but a higher CO₂ concentration, compared to those of nonmulched fields. Over the measurement period, cumulative CO₂ efflux was 1871.95 kg C·hm^-2 for mulched field and 2032.81 kg C·hm^-2 for nonmulched field. Soil CO₂ concentration was higher in mulched field (ranging from 5137 to 25945 μL·L^-1) than in nonmulched field (ranging from 2165 to 23986 μL·L^-1). The correlation coefficients between soil CO₂ concentrations at different depths and soil CO₂ effluxes were 0.60 to 0.73 and 0.57 to 0.75 for the mulched and nonmulched fields, indicating that soil CO₂ concentration played a crucial role in soil CO₂ emission. The Q₁₀ values were 2.77 and 2.48 for the mulched and non-mulched fields, respectively, suggesting that CO₂ efflux in mulched field was more sensitive to the temperature.