【Objective】Soil inorganic carbon is a vital component of the terrestrial carbon pool in arid and semi-arid regions, and its accumulation and differentiation mechanisms profoundly influence regional carbon cycling processes. Climate is the dominant factor controlling soil carbonate accumulation, but the distribution of soil carbonates is also often affected by non-climatic factors such as parent material. 【Method】To elucidate how precipitation and parent material synergistically regulate the spatial variation of soil calcium carbonate (CaCO3) at a regional scale, this study systematically analyzed the CaCO3 content, depth of the enriched layer, and their main controlling factors in 13 typical soil profiles along the precipitation gradient from the Northeast China Plain to the Inner Mongolia Plateau. ?【Result】The results showed that precipitation governed the macro-scale vertical differentiation of CaCO3, with the depth of the enriched layer exhibiting a significant positive correlation with mean annual precipitation (R2 = 0.43, P < 0.05). The total accumulation of CaCO3 was controlled by the calcium source abundance of the parent material and showed no significant correlation with precipitation. Particle size analysis further revealed that, in profiles with homogeneous parent material, the deposition depth of CaCO3 responded very sensitively to precipitation (R2 = 0.97, P < 0.05). However, in profiles with discontinuous parent material or abrupt textural changes, water movement was obstructed by physical interfaces, creating a “perching” or “retention” effect, which caused the depositional layer to deviate significantly from the value predicted by precipitation alone. ?【Conclusion】This study proposes a synergistic regulatory mechanism for the soil calcification process: precipitation regulates the deposition depth, parent material determines the calcium source supply, and soil texture modulates solute transport. This mechanism reveals the multi-factor interaction processes controlling soil carbonates in arid and semi-arid regions.