In order to evaluate the developmental toxicity of BPA and to investigate the possible mechanism of it in vitro, whole embryo culture was used for the study. The embryos that removed from mother mice on gestational 8.5d (GD8.5) and mother rats on gestational 9.5d (GD9.5) were cultured immediately in centrifugal serum (ICS) with a series of concentrations of 0, 40, 60, 80, 100 mg/L of BPA for 48 h to evaluate the embryo development and morphological differentiation. The results showed that the BPA inhibited the development of embryos in vitro and there was a dose-response relationship between concentrations of BPA. At high level (> or = 60 mg/L), BPA could delayed the growth and cardiac tube differentiation of visceral yolk sac (VYS), and induced various embryo defects, including abnormal neural system, arch, optic, flexion and small limb bud, etc. It is concluded that at high level, BPA had toxicity to mice and rat embryos in vitro. The damage on structure and function of VYS might be part of teratogenic mechanisms of BPA.