Abstract: Camellia oleifera shell (COS) is one of the byproducts after oil tea processing. The conventional disposal (incineration or landfilling) has presented the substantial environmental challenges, including environmental pollution and inefficient resource utilization. Aerobic composting can serve as the a promising strategy to convert the COS into stable compost, particularly for the resource recovery and environmental protection. However, the COS composting has is confined to the high carbon-to-nitrogen (C/N) ratio and the presence of recalcitrant compounds. It is often required for the high-efficiency and low-cost composting in the sustainable utilization of the COS. This study aims to investigate the effects of the different nitrogen sources and calcium superphosphate on the temperature, physicochemical properties, and carbon conversion during COS composting. Four treatments were established: COS alone (CK), COS + 30% pig manure (T1), COS + 1% urea (T2), and COS + 1% urea + 5% calcium superphosphate (T3). The results demonstrated that all treatments (except CK) were maintained a high-temperature phase exceeding 35 days. The pH values and electrical conductivity of the final compost products were ranged from 5.5 to 8.5 (below 4.00 mS/cm), respectively, fully meeting the environmental hygiene standards for compost. At the end of composting, the humification ratios (HR) for the CK, T1, T2, and T3 were 42.61%, 64.97%, 66.66%, and 86.92%, respectively, while the humification indexes (HI) were 17.41%, 40.24%, 54.96%, and 58.78%, respectively. The degree of polymerization (DP) increased by 199.08%, 400.71%, 198.84%, and 231.72%, compared with the initial values. The DP values for the CK, T1, T2, and T3 were 0.69, 1.68, 3.01, and 2.09, respectively. All treatments (except CK) were well-decomposed. Compared with the CK, the organic carbon degradation rate (C_loss) increased for the T1 and T2, respectively, while the lignocellulose degradation rates rose by 360.85% and 486.55%, respectively, and the humus content increased by 16.52% and 41.30%, respectively. In contrast, The the T3 increased in the organic carbon and lignocellulose degradation, respectively, compared with the T2. The first-order kinetics can well describe the organic matter degradation and humus formation during composting. The T2 exhibited the lower maximum C_loss, but the higher lignocellulose degradation rates, humus growth rates, and humification indices, indicating that the calcium superphosphate was further enhanced these transformations. Correlation analysis and structural equation modeling revealed that the nitrogen sources were facilitated the conversion of the lignocellulose into humus, thereby enhancing the humification. Specifically, the pig manure promoted the organic carbon decomposition, while the urea enhanced the cellulose and hemicellulose degradation, thereby increasing the humus content and polymerization. There was some influence of the calcium superphosphate on the compost properties. The correlations between pH and C_loss were altered to promote the organic carbon and lignocellulose degradation. The humus component transformation was also facilitated to increase the humification rates, but reduce the humus polymerization. These findings can provide a theoretical foundation to optimize the aerobic composting of the COS. The humus precursor substances were identified to clarify the microbial transformation of the lignocellulose degradation products into humus, in order to promote the efficient resource utilization of the COS. Additionally, the 130-day of composting can be expected for the significant time and space costs. Future efforts should prioritize to shortenshortening the composting cycle without compromising quality, in order to advance the aerobic composting toward the great efficiency.