The age structure and growth characteristics of Triplophysa orientalis,collected in the middle of the Yarlung Tsangpo River,were investigated by examining otolith.The results indicated that there were 7 age groups of the collected T. orientalis,and the 4-6-year-old accounted for about 80.87% of the total.According to the comparison of coefficient among linear function,exponential function,polynomial function and power function,the relationship between body length (L) and otolith radius (RO) could be expressed as L=253.81RO-26.725 (n=183,R2=0.97，P<0.001) and indicated no remarkable dissimilarity between females and males.According to the results of t-test,there was no remarkable difference between measured body length and back-calculated body length in each age group between females and males (t = 1.313,P > 0.05).However,the relationship between body length (L) and body weight (W) could be expressed as W=0.00001L2.9797 for female and W=0.00002L2.8475 for male,and indicated remarkable difference between females and males.Von Bertalanffy growth equation was more accurate than others to describe the growth of T.orientalis and the formula was Lt=151.65\[1-e-0.133(t + 0.01786)\] and Wt = 31.496\[1-e-0.133(t + 0.01786)\]2.9797 for female,Lt = 125.19\[1-e-0.177(t + 0.0695)\] and Wt= 18.787\[1-e-0.177(t + 0.0695)\]2.8475 for male.In addition,the growth inflexion points were 8.19 years for females and 5.83 years for males,and the corresponding standard lengths and body weights were 100.77 mm and 9.32 g for females,and 81.13 mm and 5.46 g for males,respectively.