Abstract: The distance coefficients of sampling plots along on ecotone transect were applied in the moving split-window technique for determining ecotone position and width in the area across the Abies faxoniana timberline ecotone in Balang Mountain, on the southeast edge of the Qinghai-Tibetan Plateau. The result showed that distance coefficients, such as Bray-Curtis percent dissimilarity, relative Euclidean distance, chord distance, squared Euclidean distance, coincide in peaks and width in the transect. Among them, the squared Euclidean distance is the best one to show the variation of ecotone in the moving split window. The peaks and widths of space coefficients are sensitive indicators for those of ecotones. Therefore, moving split-window technique is an effective method for ecotone determination and community classification.