Abstract: A 105 day growth trial was conducted to investigate the effect of dietary vitamin C supplementation on growth,body composition,tissue Vc concentration in juvenile soft shell turtle Trionyx sinensis. White fish meal basal diet was formulated and Vc were added at the levels of 0,50,100,200,400,800mg L ascorbic acid per kg diets on ascorbic acid equivalent basis in the form of phosphorylated L ascorbic acid. The experiment was conducted in triplicates at 31±2℃ and the turtles were cultured in 18 same construction concrete tanks with area 10.5m2 per each.The results showed that: 1) The supplementary dietary Vc could improve percentage of body weight increase,and there is a significant difference between the treatment with adding Vc 200mg/kg and the control( P 0.05).In addition,there was no any deficiency symptom observed in experimental turtles fed diet without or with low dietary Vc supplementation. 2) Based on broken line analysis,the minimum dietary Vc supplementation for maximum growth of juvenile soft shell turtle is 184mg/kg. 3) The Vc concentration in liver linearly increased with dietary Vc supplementation (R2=0.9542). There is a significant difference on Vc concentration in liver between the control and the treatments( P 0.05)in turtle whole body composition.