Chinese sturgeon (Acipenser sinensis) is a key protected animal at the national level in China. At present, large-scale breeding of the second generation of Chinese sturgeon has been preliminarily realized. This has significantly increased the pressure on the cultivation of the facilities of various Chinese sturgeon protection institutions. Therefore, it is important to study the suitable stocking density of adult Chinese sturgeon without affecting gonadal development to make the best use of the cultural facilities. To study the suitable stocking density of adult Chinese sturgeon [(5.61 ± 0.61) kg], three density gradients (low, middle, and high) were set up in this experiment, and the initial densities were (6.12 ± 0.04) kg/m³ , (8.92 ± 0.19) kg/m³ , and (11.75 ± 0.29) kg/m³ , respectively. After 12 months of culture, the experimental fish were transferred to the recovery pond [(4.11 ± 0.03) kg/m³ ] and re-cultured for 6 months. The growth, blood biochemical, and sex hormone levels were measured at 0, 12, and 18 months. The results showed that the densities of low, medium, and high density groups were (10.99± 0.21) kg/m³ , (13.59 ± 0.10) kg/m³ , and (17.78 ± 0.28) kg/m³ at 12 months, respectively. With the increase of designed stocking density, the body weight, specific growth rate (SGR), weight gain rate (WGR), and daily weight gain rate (DWGR) of experimental fish decreased significantly (P ＜ 0.05), while the body weight variation coefficient and feed coefficient (FCR) increased significantly (P ＜ 0.05). The concentrations of serum triglyceride (TG), total cholesterol (TC), and total protein (TP) decreased with the increase of designed stocking density. The concentration of blood glucose (GLU) in the high density group was higher than that in the middle and low density groups (P ＜ 0.05). There was no significant difference in the concentration of albumin (ALB) among the groups. The concentrations of 17α, 20β-dihydroxyprogesterone (17α, 20β-DHP) and testosterone (T) in each density group were not significantly different, but their concentrations were slightly higher than those at the beginning of the experiment. The levels of estradiol (E2), vitellogenin (VTG), and progesterone (P) in the high density group were significantly lower than those in the low and middle density groups (P ＜ 0.05), and there was no significant difference between the low and middle density groups. Differences in body weight, condition factor (CF), and coefficient of variation of body weight among different density groups were smaller than that at the beginning of the recovery period. The concentrations of GLU, ALB, TG, TC, and TP in each density group recovered to the level at the beginning of the experiment, and there was no significant difference among the three groups. The concentrations of E2, VTG, and P in each density group recovered to the same level, and there was no significant difference among the groups. The results showed that high-density culture had significant negative effects on growth and sex hormone levels of adult Chinese sturgeon but had no significant effects on medium-density and low-density groups. To maximize the utilization of culture facilities, some growth performance can be appropriately discarded on the premise of ensuring the normal development of gonads of adult Chinese sturgeon. Therefore, it is suggested that the real-time stocking density of adult Chinese sturgeon should not exceed 13.59 kg/m³ .