Abstract: Carrying capacity of reservoirs for feeding cage-culture of fish was estimated using 18 experimental enclosures,each 14.3m3 in volume and stocked with common carp. The carrying capacity was defined as the maximum possible density of cultured fish in the reservoir that does not result in violation of the“Water Quality Standard for Fisheries”(GB 11607-89).The experiment was carried out at Dongzhou Reservoir,Xintai City,Shandong Province during June 15-July 18,1990.The variations in the environmental factors,including water temperature,transparency,pH,dissolved oxygen,COD,BOD and UIA were monitored during the experiment.The carrying capacity was estimated to be about 30O0 kg·ha-1.The authors suggestthat a safty parameter of 25-35% should be used,and therefore the maximum allowable den-sity of clutured fish should be 1800-2300 kg·ha-1, as recommended to fish fanners.