Describing and understanding spatial patterns over time is an important research arena in landscape ecology. The forest-steppe ecotone with alkalized grassland in Hulunbeir, which borders the Great Xing′an forest region, is one of the most significant ecological barriers in North China. Since 1950s, the landscape patterns in the ecotone have changed greatly and ecosystem functions have degraded substantially because of excess resource development as well as natural changes. By integrating Remote Sensing (RS) and Geographic Information System (GIS), this paper explores how and why the landscape pattern changed. The results shows: (1) it is remarkable to interchange between different landscapes, especially frequently among forest land, grassland, cropland and unused land. The area of forest land has decreased sharply by 785815 km2, while the unused land increased 4087.25 km2. (2) indices of landscape characteristics have changed significantly from 1988 to 2004, with the landscape diversity index and fragmentation index increasing and the landscape dominance index decreasing.(3) Main landscape types including forest, grassland, cropland, unused land show their patches quantity added and patch shape changed more and more complexly.(4) From 1988 to 2004, the centroid of main landscape types had moved east, the centroid of forest has moved 4.48 km southeast, while the centroid of grassland moved 29.93 km northeast. This study revealed the intensities, directions, and rates of landscape pattern changes, and the relationships among landscape pattern, ecological processes, and human activities. This study can provide scientific basis for the sustainable development of the ecotone.