By nitrifying bio-floc system to culture Litopenaeus vannamei, and by setting different stocking density, the influence of nitrifying bio-floc systems was explored at different culture density on growth performance and quality of Litopenaeus vannamei. Some healthy Litopenaeus vannamei in same size[body length (4.80 + 0.25) cm, body mass (0.98 + 0.16) g] were selected to culture 45 days at five different stocking density treatments. The results showed that:In the range of 80-610 ind/m³ density, the nitrifying bio-floc system can control the Un-ionized ammonia and Nitrite-N near the warning concentration (0.2 mg/L),which improves the environment for health growth of Litopenaeus vannamei and ensure the survival rate of culture, and in addition,appropriate sewage discharge at the system can avoid the Nitrate-N concentration accumulation too fast in high density culture; In the range of 80-610 ind/m³ density, the survival rate of Litopenaeus vannamei declined with the increase of density,but the yield increased with the increase of density.