Based on the community important values and present-absent data along elevation gradient on the north slope of Changbai Mountains and using moving split-window techniques, the width and location of vegetation ecotone were discussed in this article. The results showed that the methods of Bray-Curtis Percent Dissimilarity (PD) and Squared Euclidean Distance (SED) introduced in the analysis gave the similar results. Among the methods used in the moving split-window analysis, the SED method was the best in showing the variation of ecotone. According to the results of moving split-window techniques analysis, the ecotone between broad leaved-pine forest and dark conifer forest was gradual type, located in 1120 m a.s.l., spanned 200 m.; that between dark conifer forest and Betula ermanii forest was sharp type, located in 1790 m a.s.l., spanned 50 m; and the timberline was a sharp line, located in 2000 m, spanned 40 m.