Based on RS and GIS technologies, the landsat TM/ETM satellite images in 1987, 1991, 1996, 2000 and 2003 were interpreted and analyzed using the overlap function, which showed the temporal and spatial rules of reed land change in Baiyang Lake in the last 16 years. The research result indicated that: the area of the whole reed land showed a trend of "down-up-down". Water area and cropland were the main land cover types that reed converted. Lower places in north and east parts of Baiyang Lake were the ones occurred the conversion between reed land and water area, and higher places in northwest and southwest occurred the conversion between reed land and cropland. The relationship between area of reed land and surface water level was also studied. The result revealed that there was a significant quadratic relationship between the average surface water level in the previous 2 years and the area of reed. The relationship equation is y=-0.1573x~2 215.90x-57989 (R~2=0.97). This relationship will be of great significance for controlling the area of reed land based on surface water level and improving the efficiency of using water resource in Baiyang Lake.