Using RT-PCR,the partial length vitellogenin(VTG)cDNA sequence and β-actin cDNA sequence of Colisa fasciata were cloned.VTG cDNA sequence contains 3 464 bp nucleotides and encodes 1 150 amino acids.β-actin cDNA sequence contains 1 253 bp nucleotides and encodes 375 amino acids. In vivo and in vitro methods were employed to investigate VTG mRNA expression under exposure to estradiol(E₂),octylphenol(OP),cadmium(Cd²⁺)and perfluorooctane sulfonates(PFOS)and evaluate the estrogenic activity.The results showed that E₂ and OP could induce VTG mRNA expression in dose-dependent way by in vivo and in vitro test. Cd²⁺ could induce VTG mRNA expression only in the low dose by in vivo test,but VTG mRNA expression was not observed in PFOS groups by in vivo and in vitro test.The results indicated that the strength of estrogenic effects was in the order E₂>OP>Cd²⁺. Cd²⁺ estrogenic effects in vivo and in vitroresults are inconsistent,suggesting that the mechanism of Cd²⁺ induced effects of estrogen and E₂ may be different.The results also indicated that VTG cDNA of C.fasciata is very sensitive to environmental hormone and very suitable to be a biomarker for monitoring the environmental hormones.