A survey of food organism is made in Danjiangkou Reservoir which consists of Danjiang Reservoir Region and Hanjiang Rcservir Region during December 1992 and September 1993. The results show that the production of phytoplankton, zooplankton and benthos was 1.5×10⁶ t, 3.0×10⁵ t and 4.48×10⁴ t respectively, a total of 1.845×10⁶ t; the potential fishery production reached 1×10⁴ t, 0.6×10⁴ t and 0.015×10⁴ t seperately, amounting up to 1.615×10⁴ t. Based on the standing crops of phytoplankton and bio-nutrients, the trophic type of Danjiang Reservoir region could be regarded as oligmesotrophic and that of Hanjiang Reservior region to mesotrophic. The fishery development and water quality protection in Danjiangkou Reservoir were also discussed.