【Objective】In Chongqing, changes in soil morphological characteristics of Stagnic Anthrosols derived from calcareous mudstone are not obvious from top to bottom of the soil profile in most cases. However, this phenomenon is not always so for Stagnic Anthrosols derived from limestone. Given that the reason for this difference is not clear, there is a need for further studies in this area. Therefore, this paper discusses the occurrence and evolution characteristics; types and causes of calcareous mudstone and limestone soils under rice-planting conditions, to improve the accuracy of the systematic classification and spatial distribution prediction. 【Method】Field soil surveys were conducted to identify six Stagnic Anthrosols profiles of different slope positions (mesoslope, baseslope and footslope) on limestone and calcareous mudstones and to obtain soil-forming conditions and soil morphological characteristics of the profiles. Soil samples were collected from the profiles by horizon for analysis of physical and chemical properties. According to the “Keys to Chinese Soil Taxonomy (3rd ed.)”, diagnostic horizons and diagnostic characteristics for the tested soils were determined, and the soils were attributed and named in Chinese Soil Taxonomy level by level. The soil genesis of the tested soils is discussed based on the characteristics of organic carbon mineralization. 【Result】From the mesoslope to footslope, there was very few rust mottles on the structural plane of Stagnic Anthrosols derived from calcareous mudstone (CS), and the vertical differentiation of free iron was not obvious. However, there was very few to many rust mottles on the structural plane of Stagnic Anthrosols derived from limestone (LS), and the distribution was different in different slope positions. Especially in the acid soil of the baseslope, the lower layer of free iron accumulated significantly. This showed that there were differences in iron migration characteristics between the Stagnic Anthrosols derived from the different types of parent rocks. The accumulation of organic carbon mineralization (C₁₅) of CS was significantly (P<0.05) lower than that of LS at the same slope position. The lower amount of easily mineralized organic carbon made it difficult to reduce the high valent iron in CS. Given that iron migration in the profiles was not observable, the typical soils of CS at different slope positions were classified as Typic Hapli-Stagnic Anthrosols. From the mesoslope to footslope, the C₁₅ of LS increased gradually, with C₁₅ of footslope being significantly (P<0.05) higher than that of other slope positions. Combined with the influence of slope position on water condition, the typical soils from the mesoslope to footslope were classified as Typic Hapli-Stagnic Anthrosols, Typic Fe-accumuli-Stagnic Anthrosols and Typic Gleyi-Stagnic Anthrosols. 【Conclusion】The concentration of easily mineralized organic carbon is a key factor in determining whether slope position can cause different types of Stagnic Anthrosols derived from calcium-rich mother rock. Also, some of the Stagnic Anthrosols derived from limestone have anthro-recalcification, but cannot be classified into the subcategory of “Recalcaric” based on the current standards. Therefore, it is suggested that the retrieval requirements for the adjective “Recalcaric” of the subcategory of Stagnic Anthrosols be revised.