Using the panel data of 26 provinces and eastern, central and western regions form 2000 to 2011, Cobb Douglas production?function model is adopted to analyze the influence of irrigation and water conservancy facilities on agricultural?production. The results show that the impact of agricultural production mainly comes from the effective irrigation area, disaster area and rural hydropower installed capacity; total sown area of farm crops had different influence on the agriculture?output?value in eastern, central and western regions.