<p>Composting is an effective recycling approach for citrus pruning branches, but the low degradation efficiency of citrus branches with high lignocellulose content affects humification and composting quality, yet the key regulatory factors in this process remain unclear. In this study, citrus branches with bagasse and peanut bran were composted to analyze the changes in lignocellulosic degradation rates, physicochemical properties, and microbial communities across four phases, and further evaluate the compost's effectiveness in citrus orchards. During the 63-day composting process, the lignocellulose degraded most rapidly during the thermophilic and cooling phases, varying in sync with moisture and the C/N. The co-occurrence network of bacterial communities was more stable and more effective in promoting lignocellulose degradation than the fungal community. The dominant bacterial phyla were Firmicutes, Proteobacteria, and Actinobacteria; among them, Actinobacteria, γ-proteobacteria, and δ-proteobacteria served as keystone indicator taxa during the thermophilic and cooling phases, respectively. During these two phases, the metabolic functions of the bacterial community were the strongest, particularly in carbohydrate metabolism and amino acid metabolism, resulting in a faster degradation rate of lignocellulose. Furthermore, regular application of compost significantly improved the availability of soil nutrients, increased the content of mineral-associated organic carbon by 30%, and changed the diversity and composition of soil bacterial communities dramatically. This study provides reference insights for the composting utilization of citrus branches and verifies the soil amendment efficacy of the compost. It is recommended to focus on regulating moisture content and C/N to enhance lignocellulose degradation and improve compost quality.</p>