Topmouth Culter (Culter alburnus) is an usual economic fish which distributed in most of the rivers in China. Because of the destructive fishing and environmental pollution, the population was significantly reduced. In order to study the present resource status of spawning population in the upper Yangtze River, 374 samples were collected in the Jinjiang River during January to December in 2015. The body length, body weight, net weight and ovary weight were measured. And then the body was dissected to pick out the vertebrae for age identification, the gonadosomatic index were calculated. The results showed that the reproductive periods of this fish species frequently occurred in June and July. The age distribution of reproductive population were between 3 and 6, the body length ranged from 250 to 537 mm, and the body weight ranged from 184.9 to 2 587.5 g. Sex ratio was 1.14︰1 (Table 1). There were significant differences between males and females, which expressed physically on cloacal orifice and the swelling degree of abdomen, and also by the body length to body weight equation (0.01 < P < 0.05, Fig. 1). The Logistic equation was used to calculate the characteristics of the first maturity: the body length and weight of females were 273 mm, 192.0 g and 4.2-year-old, while the males were 311 mm, 249.4 g and 3.4-year-old (Fig. 2). Absolute fecundity of matured females was from 25 067 to 54 274, and relative fecundity ranged from 24.2 to 36.9 per gram in weight, of which the average egg diameter was 1.1 ± 0.3 mm. Annual changes of gonado somatic index of the female and male groups were consistent, and the line chart increased from January to May, escalated obviously in June and reached the peak in July, but decreased rapidly in August, and then tended to be steady from September to December (Fig. 3). The egg diameter distribution of mature ovary had two distinct peak curves, which indicated the female spawns in batches (Fig. 4). Contrary to the reproductive population of fish in other rivers, the population in Jinjiang had the same reproductive periods but with a lower absolute fecundity and relative fecundity. The fecundity, egg diameter, reproductive periods and sexual diversity from different geographical populations were analyzed, and some protection strategies should be reinforced.