Hemibarbus medius is an important fish of fisheries in the Beijiang River. However, its biological characteristics are poorly known. In order to determine age and growth simulation of H. medius, 640 specimens were collected from April 2007 to March 2009 in the Beijiang River, Guangdong province. The scales were collected and used for age determination, the standard length, body weight were measured. The annual rings on the scales were formed primarily by the pattern of sparseness-denseness which was visible in the prezone region and the cut of the scales which was present on the rear-side region. The percentage of marginal increment at the scales in H. medius throughout the year showed that the annual rings of the scales mainly formed from March to April and it was formed once a year. The sex ratio of female to male is 1.23:1. The age of female was from 1+ to 6+, mainly in age of 1+, 2+, 3+and 4+, while the male was from 1+ to 5+, mainly in age of 1+, 2+ and 3+. However, there were much more females than males in age 4+-6+. The standard length of specimens ranged from8.4 to 24.3 cm, with the majority (86.20%) were less than 20cm. Body weight ranged from 10.06 to 318.80 g, but most fish (87.82%) were less than 150 g. The relationship between standard length and body weight was W＝0.011L3.149 for females , and W＝0.011L3.135 for males, and W = 0.011L3.148 for the combined sexes. Females and males did not exhibited statistically significant differences in growth. The relationship between standard length and scale radius (R) was L＝6.387 R 0.853 and L = 4.569R + 2.587. The von Bertalanffy growth arameters for combined sexes based on length-at-age data were L∞ = 29.855 0 cm, k=0.223 1 year?1, W∞ ＝483.889 8 g, and t0＝-0.928 2 year. The results of χ2-test shown that it had not statistically significant differences between the measured values of standard length, body weight and the estimated values of standard length and body weight derived from the Von Bertalanffy equations. Growth inflexion point were 4.65 years , when the standard length is about 21.3 cm, and weight 166.30 g. The standard length growth rate in von Bertalanffy functions gradually decreased with age, and the accelerated rate was below zero at all times and inclined to zero. The body weight growth rate in von Bertalanffy functions gradually increased before the growth inflexion point and then decreased, and the accelerated rate was above zero and decreased before the growth inflexion point, and then below zero. Our data suggest that the Hemibarbus medius population in Beijiang River had been overexploited. To protect the population and allow for sustainable utilization, we suggest only fish longer than 17 cm (age 3) should be harvested.