A growth trial was conducted to evaluate the optimum requirement of dietary phosphorus for juvenile red swamp crayfish,Procambarus clarkii.Triplicate groups of juvenile red swamp crayfish (initial mean weight:5.02±0.51 g,mean±SD) were fed diets containing different levels of phosphorus (0.83%,1.07%,1.25％,1.38％,1.59％,1.82％ and 2.03％) for 70 d.The results showed that both the weight gain and specific growth rate increased significantly with increasing dietary phosphorus up to 1.82% and then decreased beyond this level.Feed conversion ratio decreased significantly with increasing dietary phosphorus level up to 1.82%.Dietary treatments did not significantly affect survival rate.Body composition analysis showed that the whole-body ash and phosphorus contents were significantly affected by dietary phosphorus levels.Dietary phosphorus levels also had distinct effects on hepatopancreas alkaline phosphatase activity.Broken-line analysis based on weight gain and specific growth rate indicated that the minimum phosphorus requirement for the optimal growth of juvenile red swamp crayfish were 1.84% and 1.80%,respectively.