Estrogen participates in many life activities through combination with estrogen receptor α (ERα) or estrogen receptor β (ERβ) in the body.  In order to establish an in vitro estrogen-like compound screening model, the coding region of human ERα and ERβ was separately constructed into pET32-ERα and pET43-ERβ prokaryotic expression vector and water-soluble recombinant ERα and ERβ proteins were expressed in Escherichia coli strain BL21.  Western blotting revealed that both recombinant proteins have estrogen receptor binding sites.  The proteins were purified using S•Tag affinity Purification Kit and digested with enterokinase to get the ERα and ERβ proteins.  About 0.90 mg of ERα and 0.65 mg of ERβ were obtained at the concentration of 0.181 and 0.131 mg·mL⁻¹, respectively.