In this paper, We studied effect of the breeding density to the effect of Oplegnathus fasciatus in the growth,feeding and behaviour,at the water temperature of 23-24 ℃. The experiment was divided into four groups named D1, D2, D3 and D4, the initial desentiy was 1,2,3,4 kg/m³, respectively.The results showed that the larval Oplegnathus fasciatus mortality increased sharply beacause of the long term high density, which was disadvantageous to the lives of the larval Oplegnathus fasciatus. But at the low density, the larval Oplegnathus fasciatus growed very fast.While at the long term high density the growth was very slow, the specific growth rate dropped sharply(P<0.05).During the whole test, the feeding rate was decreased with the increase of the density in each tested group,the food net efficiency was higher in low denstiy than that in high density.In the whole test,the food net efficiency of D1 was the highest, then D2, D3, D4. We found that 6 kg/m³ was most suitable feeding denstiy of Oplegnathus fasciatus,while the density was higher than 9 kg/m³ which was unsuitable to the growth of 〖WTBX〗Oplegnathus fasciatus.