Soil parent material origins, properties and classification were discussed on the three principal runoff plots in the forests of Chinese fir, loblolly pine, and oak for long-term observations, which were not fully characterized before. The parent materials were defined as loess-like sediments(Q 3x) according to the particle and chemical analysis and the geological records. Bleaching and characterization were morphologically apparent, but not well developed as to be defined as bleached or claying horizons. Soil under oaks, compared with soils under Chinese firs and loblolly pines, showed higher nutrient concentrations (N, P and K) and humification, lower base saturation percentages and soil pH. The soils were placed in Yellow-cinnamon subgroup of Yellow-brown soil group (Soil Classification of China, 1978), Yellow-cinnamon subgroup of Yellow-cinnamon soil group (Soil Classification of China for the Second National Soil Survey, 1998) and Argillic yellow-brown soil subgroup of Yellow-brown soil group (Chinese Soil Taxonomic Classification, 1st proposal, 1991).