Abstract:A total of 332 Thymallus grubii were collected from the Huma River and the Emur River in the Heilongjiang River Basin. And 180 males, 133 females, and 19 unable to distinguish between male and female were identified. Body length, body weight, net body weight, ovarian weight, age, gonadal maturity coefficient and fullness were measured in 63 females whose gonadal development reached stage IV. The age of micro-otoliths was identified, and about 0.25 g of gonadal tissue in the anterior, middle and posterior ovaries of the females was weighed respectively and counted, and the individual fecundity was calculated. SPSS 16.0 was used to conduct multiple linear regression analysis on absolute fecundity F, the relative fecundity of body length FL, the relative fecundity Fm of body weight, and the biological indexes of female individuals, and the full regression equation was obtained, from which the index with P value less than 0.05 was screened out, and the multiple linear regression analysis was carried out again, and finally the standardized regression equation was established. Individual fecundity was fitted to seven biological indicators, and the equation with the highest fit was selected. The results showed that the breeding population of Thymallus grubii was composed of 2-4 years old individuals, and the absolute fecundity of individuals was (2 152.63±905.96) grains. The relative fecundity of body length was(11.11±3.01) grains/mm. The relative fecundity of body weight was (22.99±1.62) grains/g. Multiple regression analysis showed that the absolute fecundity of individuals was positively correlated with ovarian quality, and the partial correlation coefficient was the highest. From the best-fitting equation, it can be seen that the fitting degree between individual absolute fecundity and ovarian mass is the highest (R2=0.984 3), and the relationship is F=0.812 6 m02+ 234.09 m0+520.14, so the best-fitting equation of individual absolute fecundity and ovarian mass can be used to estimate the fecundity of wild Thymallus grubii population.