The vitellogenin of male goldf ish ( Carassius auratus ) was induced by intraperitoneal injection of 0. 05 mg..g - 1 BW of 17....estradiol dissolved in ethanol. After two weeks induction, the blood was collected from caudal vessel, then centrifuged at 8 000 r..min - 1 for 5 min. After plasma native..PAGE, the gel was stained with the method of CBB G250.., phospho.., lipo.. and glyco..staining respectively. the location of vitellogenin in the gel was identified. This method provides a practical and ef fective way of vitellogenin identif ication. The result of native.. PAGE showed that, after the injection of 0. 05 mg ..g - 1BW of 17....estradiol for two weeks, the male fish can synthesize vitellogenin. The vitellogenin average content in E2 group was 690. 2 ng ..mL - 1 by ELISA, it was signif icant ly different from male control group( P < 0. 01) , whose average content was 10. 7 ng..mL - 1 , and it was also much higher than that of the female control group, who se average content was 285. 5 ng..mL - 1 . Compared w ith control male group, the Ca2 and plasma total protein content of the E2 exposed male group was increased signif icant ly. In control group, the Ca2 contents in plasma of male and female control groups were 1. 6 mmol..L- 1 and 1. 7 mmol..L- 1, respectively. After two..weeks treatment of E2, Ca2 content of male groups was 50% higher than that of male contro l group, which was 2. 3 mmol..L - 1 . The contents of total protein in the control male and female groups were 3253. 1 mg..L- 1 and 7071. 0 mg..L- 1, respectively. After two..weeks treatment of E2, the total protein content in plasma was 9616. 6 mg..L- 1, which is 3..folder higher than that of the control male group. So E2 not only can induce male goldf ish to synthesize vitellogenin but also can alter the physical index of f ish plasma.