Plant canopy, one of most important factor influencing soil and water conservation, has been studied for a long time. Crop characteristics, with great seasonal changes through the year, influence the soil loss significantly. The purpose of this study is to measure and analyse the plant characteristics and their seasonal change in the Loess Plateau. A small watershed, Danangou in the Loess Plateau of north China, was selected for this study. Crop characteristics including plant cover, plant height and leaf area index (LAI) had been measured every two weeks in 1998,1999 and 2000. In Danangou watershed, half of the lands are used as cropland for maize, foxtail millet, pearl millet, potato, buckwheat and soybean, and the others are wasteland, fallow, shrub, woodland and orchard.For cropland, LAI, height and cover changed greatly during the measurement season. The cover of cropland increased lately and slowly during the spring, and reached their highest values in August. For non cropland,cover increased from April, arrived the high value in May or June, and kept it to September even October. Annual precipitation has big influences for the crop characteristics. The individual rainfall event also has an important effect on plant characteristics. Because cropland consists of half of the watershed, landuse condition of the Danangou is not very good for soil and water conservation.