To clarify the effects of different planting patterns on respiration and soil organic carbon (SOC) in red soil sloped farmland, a field experiment was conducted with 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 rates of carbon dioxide (CO₂), SOC contents, and the activities of enzymes related to carbon-nitrogen-phosphorus cycles of surface layer (0-15 cm) and sub-surface layer (15-30 cm) were determined. Compared with the FA, PN, SP, SPV and PS significantly reduced CO₂ emission rates and SOC contents of the surface soil, PN and SP also reduced 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 the contents of SOC and dissolved organic matter (DOC); SPV had no significant effect on CO₂ emission rate of the surface soil, but increased the contents of SOC and DOC in the surface soil, with increases of 15.3% and 11.3%, respectively. SPV increased the activities of cellobiose hydrolase (CB), BG and NAG in the surface soil. 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 CO₂ emission rate of sub-surface soil was significantly positively correlated with PER. The results of the partial least square method showed that total dissolved nitrogen (DTN) was the most important influencing factor affecting CO₂ emission rate of the surface and sub-surface soils. In conclusion, peanuts-green manure increased the surface soil respiration intensity, while sweet potatoes-green manure had no significant effect on it, but increased SOC. Therefor, in the agricultural production of red soil sloped farmland in the south, the “sweet potato-green manure” rotation model is recommended because of its advantages of increasing carbon content and reducing carbon emissions.