Abstract: To determine the content and changes of 6 steroid hormones in the ovaries of female farmed marbled eels Anguilla marmorata during artificially induced maturation through carp pituitary extract (12 mg/kg·week) and hCG(300 IU/kg·week) injection,in this paper,ultra-performance liquid chromatography coupled with electronspray ionization-triple quadruple mass spectrometry(UPLC/MS/MS) method was applied to detect the 6 steroid hormones..The results showed that the chromatographic separation of 6 gonad steroid hormones,namely,testosterone(T),progesterone(P),estradiol-17β(E₂),estriol(E₃),17α,20β-dihydroxy-4-pregnen-3- one(DHP),and 17α-hydroxyprogesterone (17α-OHP) was well performed using an xBridge C₁₈ column.The linear regression coefficients(R) of T,P,E₂,E₃,DHP,17α-OHP were above 0.99 in the range of 0-200 ng/ml and the limits of detection were above 0.1-0.5 ng/g.Average recoveries of T,P,E₂,E₃,DHP,17α-OHP also reached more than 89.00%-94.83%,and relative standard deviations were less than 20%.The average contents of T,P,E₃in the second week(after second injection) were (0.27±0.05),(0.64±0.05),(1.17±0.19)ng/g respectively.DHP,E₂,17α-OHP were not detected in the second week.From the ninth week,the contents of T,P,E₂,E₃ DHP,17α-OHP increased to (0.73±0.13),(1.28±0.270.38),(1.27±0.27),(0.83±0.14),(1.50±0.59),(1.43±0.25)ng/g.The average contents of T,P,E₂,E₃,DHP,17α-OHP in sixteenth week (after sixteenth injection) were (1.17±0.14),(2.23±0.51),(5.59±0.96),(2.46±0.70),(2.29±0.65),(4.56±0.74)ng/g,while there were no E₂ and E₃ detected in the control group.The results indicated that E₂ and E₃ are essential to ovary development,and the 6 steroid hormones increased with the development of gonad maturation.The UPLC/MS/MS method is a sensitive and reliable approach with high recovery rate in simultaneously quantifying 6 gonad steroid hormones in the fish.