) is distributed in western Pacific, including East China Sea, Yellow Sea, Bohai Sea, Japan and Korean waters. In recent years, as traditional fishery resources recession being serious, yellow goosefish is playing a more and more important role in Chinese fisheries. Presently, it is mainly captured by movable stow net, with an average yearly catch of 1.2×10⁴ t in Jiangsu and Zhejiang provinces. However, there were few studies on this species, especially on its reproduction biology.The reproduction of yellow goosefish was studied from the data collected between September 2008 and July 2009 in Southern Yellow Sea. A total of 644 specimens were studied. The overall sex ratio was close to one (>0.05), but male outnumbered female when its total length was in the range of 251−400 mm (<0.01). Moreover, there were more male specimens in October, November and December than females (<0.01). Females outnumbered males in size classes greater than 450 mm (<0.01) and no male larger than 550 mm was found, which was thought to be caused by different growth rate of female and male specimens, while females grew faster than males. The total body length of 50% male and female individuals reaching) was estimated by logistic equation. The estimated mean total body length was 332 mm for males and 483 mm for females, which indicated that the stock was vulnerable to overfishing. By analyzing the monthly changes in the values of the gonadosomatic index (GSI) and percentage of females in different gonadal stages, it was found that the reproduction of yellow goosefish took place during February and June, especially in March and April. The mean absolute fecundity and relative fecundity were found to be 614 820 ± 253 800 and 244±43, respectively. The absolute fecundity () was of apparent functional relation with total length (TL) and of linear functional relation = 122.87BW+120 287 (=0.794 5), respectively. The mean diameter of ripe gonadal eggs was 1.2 mm, which showed just one peak value, indicating this species was total spawners. Along with the development of gonad, hepatosomatic index (HSI) also changed apparently, which indicated that liver played an important role in the maturity process of yellow goosefish. The condition factor () changed apparently all through the year for females and males, which had the smallest value in February and March, respectively, corresponding to the highest GSI value.