[Objective] Lou soil is an important agricultural soil that has an apparent cumulic epipedon formed on the top as a result of long-term dung stacking therein in the Guanzhong Region of Shaanxi Province, and its classification has received much attention. In order to explore its pedogenic characteristics and attribution in the soil taxonomy and to establish a perfect representative soil system, a total of 18 typical Lou soil profiles were selected in the region.[Method] Of the 18 soil profiles, natural soil forming factors and morphologies were studied and in reference to the Manual of Field Soil Description and Sampling, soil samples collected for analysis of physicochemical properties in reference to the Soil Survey Laboratory Methods. On such a basis, diagnostic horizons and diagnostic characteristics of the selected soil profiles were determined, and their attributions in the Chinese Soil Taxonomy (CST) at the higher and basic category levels defined.[Result] The selected Lou soil profiles were found to have 2 diagnostic surface horizons (cumulic epipedon, ochric epipedon), 3 diagnostic subsurface horizons (argic horizon, calcic horizon and cambic horizon) and 6 diagnostic characteristics (calcaric property, redox features, mesic soil temperature regimes, ustic soil moisture regimes, cumulic evidence and calcic evidence). Thickness of the cumulic epipedon was the key indicator for determining attribution of the Lou soil at the order level. Of the 18 profiles, 13 were sorted into orthic anthrosols with a corresponding cumulic epipedon diagnostic horizon, 4 into ustic argosols, and 1 into ustic cambosols with a corresponding 20~50cm thick cumulic epipedon. They were attributed to 3 subgroups (Calcic Earth-cumuli-Orthic Anthrosols, Mottlic Earth-cumuli-Orthic Anthrosols and typic Earth-cumuli-Orthic Anthrosols) under Group Orthic Anthrosols, one to Subgroup Cumulic Hapli-Ustic Argosols under Group Ustic Argosols and one to Subgroup Typic Hapli-Ustic Cambosols under Group Ustic Cambosols. According to the criteria for sorting at the soil family and soil series levels in CST, they could be sorting into nine soil families (clay loamy mixed type mesic temperature-Calcic Earth-cumuli-Orthic Anthrosols, etc.) and 18 soil series (Yangling series, etc.). Attributes of the Lou soil profiles in the CST and the Chinese Soil Genetic Classification (CSGC), did not always match, for example, three different soil series (Yangling series, Zhenyuan Series and Linping Series) in the CST corresponding to the same soil species (Red oil soil) in the CSGC. The statistics of 71 Lou soil profiles in relevant literatures shows that the cumulic epipedons in the Lou soils varied in range of 17-97 cm in thickness, and averaged to be 50.07 cm.[Conclusion] Compared with the Chinese Soil Genetic Classification, the Chinese Soil Taxonomy reflects and characterizes more accurately differences between the soils in soil development process and degree. The criterion of 50 cm thick cumulic epipedon is appropriate for classification of Lou at high levels soil. In order to improve the ability and accuracy of classification of prototype soils with cumulic phenomenon, it is suggested that the subgroup of Cumulic-Hapli-Ustic Cambosols under Group Hapli-Ustic Cambosols should be added in the CST.