Experiments in Comprehensive fishery exploitation were conducted in Hei Long Tan Reservoir (1693hm²) from 1991 to 1995.The major results are as follows; determination of aquatic biological productivity and fishery resources and estimation of maximum potential fish production, effect of water physi-chemical properties and water level change on fish yield and plankton community structure, intensive culture of carp. grass carps and bream in net-cages, and discussion of the comprehensive fishery exploitation of large-scale reservoirs of multiple function.As a result, the total fish yield of the reservoir has increaced from 622000kg to 1255 000kg, and the average fish yield gone up to 750kg/hm².