Abstract: Geographical information system(GIS)combined with Geostatistics were applied to reveal the spatial and temporal variability of soil fertility quality in the topsoil(0～20cm)in the northeastern area of China during last two decades.Soil fertility quality indices in this study include pH,organic matter,available P,available K and clay.The results show that soil pH,organic matter and available K significantly decrease during the past 20 years while the available P increases with the biggest variation coefficient.The areas with the first and second grade of soil fertility quality were over 80% in 1980,whereas nearly 98% belonged to the second and third grade in 2000.So the soil fertility quality has declined in this area due to the intensive cultivation in the past 20 years.