In order to study reproductive characteristics of Hypophthalmichthys molitrix, 433 samples were collected at the Yichang section in the Yangtze River during March 2014 to September 2016. The data for standard length, body weight, net body weight and gonad weight of each specimen, and eggs′ diameter of 10 females in Ⅳ stage were measured. Egg diameters were measured with the Image-Pro Plus 6.0 software. The gonads′ stage was divided into six stages according to the method of YIN Ming-Cheng (1995). Statistic analysis of all data were taken by Microsoft excel 2007 and SPSS 16.0. The results proved that females spawned from May to August, peaked in June and July. The age of reproductive group consisted of 3, 4, 5, 6 and 7 years, while those at 3 years were consisted a highest percentage. The sex-ratio of females to males was 1.43︰1 (χ2, P < 0.01). A significant differences were found between males and females by the body length to body weight equation (0.01 < P < 0.05, Fig. 2). The Logistic equation was used to calculate the characteristics of the first maturity and found out the minimum size of mature female was 482.3 mm in length and 2 206.7 g in weight, while that of mature male was 484.0 mm in length and 1 677.5 g in weight (Fig. 3). The average egg-diameter in ovary at stage Ⅳ was from 0.57 to 1.332 mm (average 1.01 ± 0.12 mm) and the distribution of eggs diameter showed a one peak curve (Fig. 6). H. molitrix belonged to total spawners based on the gonadosomatic index curve (Fig. 5) and the distribution of the diameter of mature eggs. The absolute fecundity ranged from 102 351 to 767 200 eggs (average 477 662 ± 9 631 eggs) and the relative fecundity per gram ranged from 44.89 to 139.75 eggs (average 93.38 ± 5.92 eggs). The absolute fecundity was power correlated to body length and body weight (Fig. 4). Contrary to the reproductive population of fish in other section of Yangtze River, the average egg-diameter of H. molitrix was relatively smaller, but the fecundity was relatively higher.