Forest litter is an important factor affecting soil microbial community and organic carbon content, and plays an important role in soil organic carbon formation and microbial growth and reproduction. The changes of soil organic carbon content and microbial community during litter decomposition have become the focus of current forest ecology research,but the extent and mechanism of its role are still unclear. It is of great significance to analyze the carbon cycle and resource management of the forest ecosystem. This study aimed to study the differences of soil organic carbon content and carbon source utilization by soil microorganisms under litter removal and addition treatments, to clarify the effects of litter removal and addition on the metabolic function and diversity of soil microbial community, and to preliminarily explore the metabolic mechanism of soil microbial community under different treatments. We hypothesized that soil organic carbon content was affected by the functional diversity of soil microbial community when litter input changed. The surface soil of the mixed forest of Catalpa chinensis and Quercus mongolica in the altitude range of 1405-1435 m in Wuling Mountain, Chengde City was selected. Using incubation combined with the Biolog-ECO method, the content of soil organic carbon (SOC) and the average well color development (AWCD) value of the microbial community, Shannon-Wiener index, Simpson index, Mclntosh index and Pielou index of the microbial community were measuredon the 21st day of cultivation. The changes of the soil organic carbon content and microbial functional diversity under different treatments of litter during the cultivation period were analyzed. The results showed that 1) different litter treatments had significant effects on the soil organic carbon content and soil microbial community diversity (P<0.05), DL > HL > NL > CK; 2) There were significant differences in the metabolic activity of soil microbial community and the utilization of carbon sources by soil microorganisms under different litter treatments (P<0.05). The carbohydrate and amino acids were the main carbon sources of soil microorganisms; 3) There was a positive correlation between soil organic carbon content and soil microbial diversity. The effects of double litter addition on soil microbial diversity were difficult to reach a significant level in the short term, and it inhibited the metabolic activity of soil microbes to a certain extent. The functional diversity of soil microbial communities had an important impact on soil organic carbon content. The results of this study can provide scientific basis and practical reference for the sustainable management of the mixed forest of Catalpa chinensis and Quercus mongolica.