Karst areas are one of the most fragile regions in the world.The karst environment is very common in southwest China where poverty and environmental degradation are prevalent.Thus,it is necessary to monitor karst ecosystem conditions and its ability to provide goods and services for society.In this paper,we analyzed the spatial distribution of organic productivity values (OPV) in Northwest Guangxi,China in 1985,1990,2000 and 2005,with Landsat TM images using remote sensing and geographic information system (GIS) techniques.Results showed that the OPV first decreased and then increased over time but the OPV of 2005 was less than that of 1985.The OPV was 184.85 million Yuan,117.53 million Yuan,163.66 million Yuan and 177.25 million Yuan in 1985,1990,2000 and 2005,respectively.Woodlands and shrubs were the two largest contributors to total OPV with total ratios of 70.51%,69.13%,73.92% and 66.23% in the four years.The OPV of residential and barren rock were low with total ratios of only 0.70%,0.56%,0.57% and 0.90%.The OPV declined from west to east,from mountain to peak-cluster depression areas,and increased in typical karst areas,but distinctly decreased in non-karst areas.Our study indicates that ecosystem conditions are improving because of the application of rocky desertification control policies,such as ecological migration and returning farmland to forest.