Based on the basic data of fishery resources by set-nets in Northern Hangzhou Bay from May to August, 2017, a preliminary analysis of biological characteristics of reproductive stocks of Collichthys lucidus was carried out. The results indicated that body length of reproductive stocks of Collichthys lucidus ranged from 87 to 150 mm, and average body length was (116.4±9.9) mm, while body weight of reproductive stocks of Collichthys lucidus ranged from 12.6 to 53.3 g, and average body weight was (27.4±7.2) g. There was an increasing trend of average body length and body weight, and independent T-test displayed a significant difference in average body length and body weight between May and August. Sex ratio (female:male) of Collichthys lucidus was 2.53:1, the number of female was significantly higher than the number of male. According to chi-square test, sex ratio was not 1:1. The gonad maturity stages of female was mainly from Ⅳ to Ⅴ, accounting for 78.2%, and the gonad maturity stages of male was mainly from Ⅲ to Ⅳ, accounting for 97.9%, and body length of individuals whose gonad maturity stages had achieved Ⅳ or above mainly ranged from 100 to 130 mm. The feeding levels of reproductive stocks of Collichthys lucidus was mainly 0 and 1, accounting for 72.8%, and the empty stomach ratio was 39.8%. The research showed that Northern Hangzhou Bay was the feeding ground of Collichthys lucidus. Collichthys lucidus has become smaller, and management for protection of reproductive stocks of Collichthys lucidus in Northern Hangzhou Bay should be enhanced.