Abstract:The distribution pattern of natural ramet population in the rhizomatous herb, Thermopsis lanceolata R.Br., at 5 scales (0.2 m, 0.4 m, 0.6 m, 0.8 m and 1.0 m) was investigated using grid samphng and spatial auto-correlation analysis (Moran‘ s I) in Maowusu sandland of Inner Mongolia of China. The result showed that the ramet population had non-random distribution pattern at four scales (0.2 m, 0.4 m, 0.6 m and 1.0 m). The most frequently observed pattern was contagious at the scale of 0.2 m. The genet had sympodial growth and nearly phalanx architecture. The branching angle of the rhizomes was from 10˚ to 30˚.The density of the ramet population was from 35 to 131 ramets·m－2. The mean height of ramets was between 11.0 cm and 25.9 cm. The biomass of the ramet population was 263.63 g·m－2 and 306.19 g·m－2 in the two plots, respectively. 33.71% and 44.97% of the biomass allocation to rhizomes were observed and the biomass allocation to roots was 29.91% and 29.95% and that to leaves was 25.12% and 36.35% in the two plots, respectively. The ratio of root to shoot was 0.44 in both plots while the ratio of below- to above- ground biomass was 2.12 and 3.59, respectively.