The electrophoretic analysis, variations of protein and nucleic acid contents with sexual maturation, of the liver tissue of male, and of the muscle tissue of male and female B. pectinirostris(Linnaeus) were investigated. As the result of protein analysis of the liver and muscle tissue of male by the SDS-PAGE electrophoretic analysis, the protein of the liver tissue of male was presented 15.8-101.5kd in molecular weight, and appeared 19 bands in all. The protein bands of the muscle tissues of male and female were almost same, their bands were presented 16.9-116.5kd in molecular weight, and appeared 23 bands in all. And in the liver tissue, the protein contents of the liver tissue of male appeared the maximum in June(the mature stage) and afterwards decreased gradually in July(the spawning stage) and August(the degenerative stage). In the muscle tissues of male and female protein contents were shown the maximum in June, and afterwards decreased gradually, the minimum in July, increased a little in August. The total RNA contents of the liver tissue of male, and their contents of the muscle tissue of male and female appeared the maximum in June(the mature stage), and afterwards decreased gradually in July(the spawning stage) and August(the degenerative stage).