Abstract: For investigating the community structures of phytoplankton in different densities intensive aquaculture ponds of yellow catfish （Pelteobagrus fulvidraco）, the Juvenile yellow catfish of 16.7 body weights and 10.8 body lengths were randomly divided into three ponds for 142 days（from May to September in 2018） with initial density of 125 000 fries/hm²（D1）, 100 000 fries/hm²（D2） and 75 000 fries/hm²（D3）, respectively. The results showed that the three ponds were dominated with green algae. The growing rate of both species quantity and richness decreased with the increasing stocking density. The diversity indexes（H’） and evenness indexes（J’） in eutrophication assessment presented high similarity and correspondence. The eutrophication degree of three ponds increased with the stocking density but not reached the level of heavy pollution which indicated that the stocking density had no significant effect on the stability of the phytoplankton community structure. The WGR （weight gain rate）,SGR （specific growth rate）, CF （condition factor） showed decreasing trends with the increasing stocking density, while the FCR（feed coefficient rate） showed increasing trend. The survival rate had no significant difference in the three ponds which were all above 90%. The SGR（specific growth rate） presented significant differences in D1,D2 and D3 group（P<0.05）, and the WGR, CF and FCR in D3 showed significant difference with those of D1 and D2（P<0.05）. According to comprehensive analysis on phytoplankton community structures and growth indexes, the optimal stocking density of Pelteobagrus fulvidraco was D2 （100 000 fries/hm²） under the conditions of this experiment.

Key words: Pelteobagrus fulvidraco, stocking density, phytoplankton, growth