Abstract: In the context of China's dual-carbon goals, plastic restriction policies, and ongoing waste sorting initiatives, aerobic composting serves as a crucial approach for the valorization of organic solid waste. However, this process faces two challenges: a bottleneck in humification efficiency caused by lignocellulose recalcitrance, and an urgent need to accelerate the degradation and transformation of biodegradable plastics under realistic conditions to minimize residues in the final product. This review systematically summarizes the key mechanisms of lignocellulose depolymerization and humus formation, alongside the transformation pathways of biodegradable plastics during physical abrasion, chemical oxidation, enzymatic depolymerization, assimilation, and mineralization. This analysis indicates that while these two substrates differ in origin and composition, they share several common degradation bottlenecks, including the difficulty of depolymerizing recalcitrant components, limited substrate accessibility, and insufficient synergy between hydrolysis and oxidation. In lignocellulose, lignin forms a barrier around cellulose and hemicellulose, restricting subsequent hydrolysis; similarly, in biodegradable plastics, initial activation and chain scission are hindered by high hydrophobicity, stable molecular chains, and limited surface accessibility. Consequently, this review highlights the unique advantages of white-rot fungi in transforming complex polymers via their nonspecific extracellular oxidative enzyme systems (e.g., manganese peroxidase, lignin peroxidase, and laccase). These fungi disrupt the lignin barrier, enhance substrate reactivity, and promote the subsequent hydrolysis of cellulose and hemicellulose. Furthermore, they increase the hydrophilicity of biodegradable plastics and weaken molecular chain stability through surface oxidation, thereby facilitating subsequent hydrolysis and transformation. Therefore, white-rot fungi theoretically possess the potential to simultaneously enhance lignocellulose humification and the degradation and transformation of biodegradable plastics. However, current evidence for white-rot fungi-mediated plastic degradation is derived primarily from controlled culture systems, and the fungi's functional stability and practical applicability under real composting conditions remain insufficiently studied. Finally, this review summarizes the main limitations of their engineering applications, including the mismatch between their optimal temperature window and the thermophilic phase of composting, competitive exclusion by indigenous microbial communities, and localized colonization and enzyme production effects caused by compost heterogeneity. To address these issues, several optimization strategies are proposed: strain screening and acclimation, the development of carrier or catalytic materials to establish stable microenvironments, and phased inoculation combined with refined control of process parameters. Ultimately, this review provides a systematic understanding of white-rot fungus-mediated compost enhancement strategies, offering technical insights to support the coordinated valorization of organic solid waste and the low-risk, end-of-life management of biodegradable plastics.