Abstract: The flora and the spatial distribution of the invasive specie Rumex nepalensis in Sewalongba Valley, an important alpine summer rangeland in Dimaluo village, Gongshan County, northwest Yunnan Province were investigated in August 2003. It was showed by the results that Rumex nepalensis appeared in 45% of the total sampled quadrates, and the coverage of the invasive species was over 25% of the surface area in 9% of the quadrates sampled. The occurrence of Rumex nepalensis was positively correlated with the degraded grassland landscape, the grazing intensity, and with the distance from the herdsman houses, whereas it was negatively correlated with the elevation and gradient of the slopes. The distribution and expansion of Rumex nepalensis was affected by local traditional grazing regimes.