A long-term field experiment was conducted to study the effects of different soil amendments (biochar and calcium peroxide) on soil labile organic carbon fractions and soil enzymes activities associated with carbon cycling in upland red soil in Jiangxi Province in order to resolve the problems of low fertility and productivity. 9 treatments were included in the experiment, i.e. CK, C0Ca1, C0Ca2, C1Ca0, C2Ca0, C1Ca1, C1Ca2, C2Ca1 and C2Ca2. The results showed that single application of biochar and combined application of biochar and calcium peroxide were beneficial to increase organic carbon content and labile organic carbon fractions, and the effects were better than single application of calcium peroxide. Soil organic carbon contents increased significantly under C2Ca0, C2Ca1 and C2Ca2 treatments. Biochar and calcium peroxide significantly increased soil labile organic carbon fractions. The content of microbial biomass carbon averagely increased by 45.22% in C1Ca0 treatment, the content of dissolved organic carbon averagely increased by 21.34% in C1Ca2 treatment, the content of particulate organic carbon averagely increased by 20.72% in C1Ca0 treatment, the content of labile organic carbon averagely increased by 22.19% in C2Ca2 treatment. Biochar and calcium peroxide increased averagely carbon management index by 11.09% and 14.07% in 0-10 cm and 10-20 cm soils, respectively. The enzyme activities were promoted with the addition of the biochar, and the effects of 0-10 cm soil layer was more obvious than 10-20 cm soil. The combined application (C2Ca2) significantly improved the activities of amylase, cellulase and β-glucosidase, while the C1Ca1 treatment significantly improved invertase activity. Therefore, biochar and calcium peroxide can effectively improve labile organic carbon fractions and enzymes activities associated with carbon cycling in upland red soil, and their combined application is more helpful in soil improvement.