Soil carbon-nitrogen-phosphorus (CNP) ecological stoichiometry is an effective means of reflecting soil nutrient status, transformations, and limitations, but the effect of returning ancient rice terraces to forest on soil CNP stoichiometry is still unclear at the aggregate scale in the subtropical hilly areas of southern China. This study explored how the CNP content and stoichiometry of soil water-stable aggregates responded after returning ancient rice terraces to forest in the soil layer depth of 0–60 cm in subtropical hilly areas. The results showed that the stability, soil organic carbon (SOC), total nitrogen (TN), C/P, and N/P ratios of soil aggregates decreased significantly with soil depth in ancient rice terraces, Chinese fir (Cunninghamia lanceolata), and moso bamboo (Phyllostachys pubescens). The proportion of macroaggregates decreased gradually and the proportion of microaggregates increased significantly after the soil depth increased. Returning ancient rice terraces to Chinese fir was more conducive to increasing the SOC, TN, C/P, and N/P ratios of soil aggregates, which may be related to plant litter biomass. Eta squared analysis showed that soil depth had a greater impact on soil aggregate stability (34 %, 38 %, and 46 %), CNP content (34 %–45 %), and stoichiometry (34 %–57 %) than land use types and their interactions. These findings indicated that returning ancient rice terraces to Chinese fir and moso bamboo can significantly alter soil water-stable aggregate stability, CNP content, and stoichiometry, and soil depth plays an extremely important role in changing them. Future research should focus on the ecological impacts of soil depth on agroforestry ecosystems.