Abstract: Soil organic carbon (SOC) represents 25% of the potential of natural climate solutions, improvement of SOC storage is a critical pathway to realize “carbon neutralization”. Reasonable SOC management and accurate model prediction require deep understanding of soil carbon cycling processes. However, the persistence mechanism of SOC, pathways controlling SOC formation, and their environmental regulations are not clear. Here, we first synthesized the frontier theories and mechanisms of SOC stabilization (biochemical recalcitrance, mineral protection, and aggregation protection) and formation (humification, microbial efficiency-matrix stabilization framework, and microbial carbon pump theory); we then reviewed the development of soil carbon cycling models (Century model, microbial model, and microbial-mineral model); we finally proposed the urgent scientific question for future experimental and modelling studies.