In order to provide a theoretical basis for soil edaphon community improvement and a fertilization system establishment for arid areas in south China, a field experiment was conducted to determine the effects of biogas slurry returning systems on the metabolic characteristics and functional diversity of soil edaphon communities in upland red soil.The experiment contained six treatments:nofertilizer (CK), chemical fertilizer (NPK),15% biogas slurry N+85% chemical fertilizer N (BS15), 30% biogas slurry N+70% chemical fertilizer N (BS30), 45% biogas slurry N+55% chemical fertilizer N (BS45), and 100% biogas slurry N (BS100). Each treatment included the same amounts of N-P₂O₅-K₂O=120-90-135 kg/hm²(except for CK).Average well color development (AWCD), indexes of microbial functional diversity (Shannon index, Simpson index, richness index) were determined, and principal component analysis (PCA) and clustering analysis were conducted. The results showed that the AWCD value of treatments BS45 and BS30 was significantly higher than that of CK and NPK treatments, respectively. Treatments BS15 and BS100 showed no significant difference to CK and NPK treatments, respectively. The order of AWCD value, Richness index, Shannon index, and Simpson index wereall the same as follow:BS45 > BS30 > NPK > CK > BS100 > BS15. The results of PCA and clustering analysis showed that the functional diversity of soil edaphoncan develop into 4 groups:First were treatments BS45 and BS30 with the highest microbial activity, which promoted microbial activity to metabolize the carbon sources of carbohydrates, amino acids, polymers and amines; Second were treatments NPK and CK with second highest microbial activity; Thirdwas treatment BS100 with the third highest microbial activity, and fourth was treatment BS15 with the lowest microbial activity. Combined with the PCA score, the order of functional diversity of edaphon communities was BS45 > BS30 > NPK > CK > BS100 > BS15. Overall, we conclude that the microbial activity and functional diversity of upland red soil was significantly affected by biogas slurry application, and that the chemical fertilizer was not completely replaced by biogas slurry. The soil microbial activity reached the highest level when the total nitrogen input ratio of biogas slurry to chemical fertilizer rangedfrom 30% to 45%, which could be expanded inupland red soil of south China.