Abstract:In this paper, 9 typical profiles of dark loessial soil were selected, field soil survey was conducted, morphological characteristics of soil profiles were observed, physicochemical properties of horizon samples were measured, diagnostic horizons and diagnostic characteristics were determined and soil taxonomy were decided for the studied soil profiles. The results showed that deep humus layers of 9 dark loessial soil profiles were identified with the thickness of 30-120 cm, and strong calcaric reactions were found with the CaCO3 content ranged from 12.5 g/kg to 189.5 g/kg, simultaneously, 6 of the 9 profiles were characterised by artificial surface accumulation during agricultural activities with the cumulic layer ranged from 30 cm to 45 cm. For the selected dark loessial soil profiles, 2 diagnostic surface horizons (ochric epipedon, mollic epipedon), 3 diagnostic subsurface horizons (argic horizon, calcic horizon and cambic horizon) and 7 diagnostic characteristics (calcaric property, isohumic property, salic evidence, mesic soil temperature regimes, ustic soil moisture regimes, cumulic evidence and calcic evidence) were determined. One soil profile was sorted into Ustic Argosols and 8 profiles were sorted into Ustic Cambosols. Only one subgroup (Typic Calcic-Ustic Argosols) was attributed for the Ustic Argosols, while three subgroups (Calcic Mollic-Ustic Cambosols, Calcic Hapli-Ustic Cambosols and Typic Hapli-Ustic Cambosols) were attributed for the Ustic Cambosols. According to the criteria for establishment of soil families and soil series in CST, 7 soil families (clay loamy mixed type mesic temperature-Typic Calcic-Ustic Argosols, loamy mixed type mesic temperature-Calcic Hapli-Ustic Cambosols, etc.) and 9 soil series (Hujiamiao series, Yaoxian series, etc.) were established of the selected soil profiles. However, the sorted results of the studied soil profiles based on CST did not revealed the essential characteristics of deep humus layer and cumulic evidence for the dark loessial soil, therefore further researches are needed to emphasized soil taxonomy of the dark loessial soil, so we suggested that the subgroup of Cumulic-Hapli-Ustic Cambosols or the subgroup of Cumulic-Ustic Cambosols been added in the CST in order to further reflect the effects of human agricultural activities on soil formation in the Loess Plateau.