The Amur sturgeon, Acipenser schrenckii, is a large freshwater fish which inhabits the Amur River basin and has been listed in Appendix II by CITES (the Convention on International Trade in Endangered Species of Wild Fauna and Flora). Currently, the artificial aquaculture of the sturgeon has been developing rapidly in China, but little information is available about the nutrient requirements of the fish. Phosphorus is an essential nutrient for proper mineralization and many other physiological functions for fish. Here the dietary phosphorus requirement of juvenile Amur sturgeon has been determined by a feeding trial. Six experimental isonitrogenous and isoenergetic purified diets were formulated containing increasing contents of phosphorus (0.18%, 0.40%, 0.71%, 0.98%, 1.38% and 1.66%, respectively). Monocalcium phosphate was used as dietary phosphorus source, casein and gelatin as protein source, dextrin as carbohydrate source, and soybean oil and maize oil as lipid source, respectively. Each experimental diet was fed to triplicate groups of 20 Amur sturgeon juveniles with initial weight approximately 4.7g in 400L aquaria and maintained at 25.6±2.0℃ for 8 weeks. The results showed that the weight gain rate, feed efficiency and specific growth rate of the juveniles increased significantly with the increases of the dietary phosphorus level (P<0.05). These values reached the peak when the juveniles were fed the diet supplemented with 0.98% phosphorus, and then decreased significantly with the further increases of the dietary phosphorus level (P<0.05). The survival rate of the fish fed the control diet (0.18% phosphorus diet) was significantly lower than that of the fish fed the other diets (P<0.05). Supplementation of dietary phosphorus had no significant effect on the muscle moisture, crude protein, or crude lipid content of the juveniles (P>0.05). The fish fed the diets supplemented with 0.71%-1.66% dietary phosphorus had significantly higher ash, calcium, and phosphorus contents in vertebra than those fed the control diet and the 0.40% phosphorus diet (P<0.05). Broken-line regression analyses of these data indicated that the dietary phosphorus requirement for optimal growth and phosphorus content in vertebra of juvenile Amur sturgeon was 0.88%-1.00% of dry diet.