【Objective】The relationship between soil organic carbon and iron oxides is crucial to the regulation of soil carbon stability. In terrestrial ecosystems, subsoil is an important organic carbon reservoir, which has been paid increasing attention due to its dynamic processes. However, little is known about how carbon inputs affect the interactions between soil minerals and organic carbon, especially in the subsoil.【Method】To address the knowledge gap, this study investigated the effects of two different crystalline forms of iron oxides, goethite and ferrihydrite, on the priming effect of topsoil (0~10 cm) and subsoil (20~40 cm) in subtropical forests. We incubated the soils by adding 13C-labeled glucose to quantify the intensity of the priming effects in a laboratory experiment.【Result】The results show that the priming effects of topsoil and subsoil were 1.63 mg·g−1and 0.61 mg·g−1, respectively, indicating that the priming effects decreased with soil depth. An interactive effect was observed between the type of iron oxides and soil depth on the priming effect of SOC. In topsoil, the addition of goethite significantly decreased the intensity of the priming effect (P < 0.05), while ferrihydrite showed no significant influence on it. In the subsoil, the addition of ferrihydrite significantly increased the intensity of the priming effect (P < 0.05), but the addition of goethite had no significant effect on the priming. In topsoil, after goethite was added, the co-precipitation produced iron-bound organic carbon, which inhibited the mineralization of organic carbon, influenced microbial carbon limitation, and further decreased the intensity of the priming effect. In the subsoil, the intensity of the priming effect was influenced by the limitation of microbial carbon and phosphorus. Glucose acted as an electron shuttle, increasing iron reduction and CO2 production. The reduction and dissolution of ferrihydrite reduced the protective effect of iron oxide on SOC, which in turn enhanced the mineralization of SOC. Iron oxides can increase SOC accumulation and stability through mineral protection and lead to SOC mineralization through redox reaction.【Conclusion】Overall, the priming effects of topsoil and subsoil have different responses to iron oxides, and the influence of iron oxides on organic carbon accumulation is affected by their properties and soil conditions.