To clarify the effects of different planting patterns on respiration and soil organic carbon (SOC) in red soil sloped farmland, a field experiment was taken as the research object and set up six treatments, namely fallow (FA), peanut (PN), peanut + green manure (PNV), sweet potato (SP), sweet potato + green manure (SPV), and sweet potato + peanut (PS). The emission rate of carbon dioxide (CO2), SOC, and the activities of enzymes related to the carbon-nitrogen-phosphorus cycle of surface layer (0-15 cm) and sub-surface layer (15-30 cm) were determined. Compared with the FA treatment, the PN, SP, SPV and PS treatments significantly reduce the CO2 emission rate and SOC of the surface soil, PN and SP treatments also reduce the activities of β-1, 4-glucosidase (BG), peroxidase (PER), N-acetyl -β-D-glucosidase (NAG), and acid phosphatase (ACP) in the surface soil. Compared with not growing green manure, PNV significantly increased CO2 emission rate of the surface soil by 29.9%, but had no significant effect on SOC and dissolve organic matter (DOC). SPV had no significant effect on the CO2 emission rate of the surface soil, but increased the contents of SOC and DOC in the surface soil, with the increase rates being 15.3% and 11.3% respectively. SPV treatment increased the activities of cellobiose hydrolase (CB), BG and NAG in the surface soil. The CO2 emission rate of surface soil was significantly positively correlated with NAG, ACP, BG and CB, and significantly negatively correlated with phenol oxidase (POX), while the CO2 emission rate of sub-surface soil was significantly positively correlated with PER. The results of the partial least square method show that total dissolved nitrogen (DTN) is the most important influencing factor affecting the CO2 emission rate of the surface and sub-surface soil of red soil sloped farmland. Therefore, peanuts + green manure increases the surface soil respiration intensity of red soil sloped farmland, while sweet potatoes + green manure have no significant effect on soil respiration intensity, but increases SOC. In the agricultural production process of red soil sloped farmland in the south, the "sweet potato - green manure rotation" model is recommended, which has the advantages of increasing carbon content and reducing its emissions.