There was less vegetation on the bare slope of mountainous area due to sterile soil in Beijing than other places. Soil and water loss was so serious that vegetation restoration became important one of ecological engineering. So experiment was executed to plant eco-grass on the bare slope in Miyun reservoir watershed and Guanting reservoir watershed, and study effect of eco-grass on soil and water conservation. The results indicated that vegetation restored quickly on the bare slope of mountainous area after eco-grass planted for a year, roughness length on the earth’s surface increased, and soil and water loss reduced clearly. Meanwhile soil bulk density reduced, and soil infiltration and available nutrients increased obviously. So soil physical and chemical properties improved batter in a short time than no eco-grass.