In this paper, we studied effect of the breeding density and water quality to the effect of Epinephelus coioides in the growth, feed coefficient and immunity. Total 450 groupers which average weight was 146.3 g/tail were divided to three experiment densities. The initial densities were 14.6, 21.7 and 29.5 kg/m3, respectively. The results showed that, under the same experiment conditions, higher stocking densities have a negative effect on fish growth. The special growth rate of the three treatments was 1.07, 0.60 and 0.47, respectively. With the augment of density, the weight of experiment groups showed a significant difference, in which the weight gain of each treatment was 118.5, 63.3 and 44.1 g, respectively. It was also found that the stocking density had insignificant impact on feed coefficient rate and survival rate. In addition, the feeding rate of Epinephelus coioides showed a significant negative correlation with the ammonia-N maintained time and concentration, but showed no direct contact with the stocking density. The immunity content of lysozyme (LZM), alkaline phosphatase (AKP) and superoxide dismutase (SOD) decreased with increased density, and showed a trend of increased at first and then decreased with the extension of culture period.