The spatial and temporal variations of soil erosion were investig ated by taking Xingguo County , Jiangxi Province as a research area .Remote sensing and GIS techniques were applied in the study of the county area of 3215 km² .Remote sensing data of six years such as black-w hite aero-photograph , MSS images and Landsat TM data were obtained .Interpretatio n characteristic indexes were established f rom remo te sensing images .Results showed that from 1958 to 2000 , changes in the eroded area may be divided into two dif ferent periods .First period ranged from 1958 to 1982 , and the soil erosion area was increased to about 2000 km² .Second period ranged from 1982 to 2000 .During the period , the county was ratified as a national representative region for cont rolling soil erosion.The total erosion area of the county was decreased by 739 km² during the 18 years , which implied an average decrease of 42 km² per year .The erosion areas for five grades were found to be somewhat decreased through comparing soil erosion map in 1992 with that in 2000 .Soil erosion grades in about 34%of soil erosion area were subject to change , and the change was dominated by one of the grades .Soil erosion grades in about 66%of soil erosion area were not changed .This means that soil erosion in this county is lowering obviously .