Objective: To study the effects of polychlorinated biphenyls on the skeletal development of zebrafish embryo and the expression of bone morphogenetic protein(BMP)-2 and BMP-4 genes. Methods: Zebrafish embryos were separately exposed to 0.125 mg/L,1.000 mg/L PCB1254 or pure water. Embryos were assessed for changes in embryonic survival and spinal deformity rate. BMP-2 and BMP-4 genes were assessed at 120 hours post-fertilization. Results: ① Low levels of polychlorinated biphenyls did not cause obvious changes of the survival or spinal deformity rate;② The survival rate declined and the spinal deformity rate increased obviously when zebrafish embryos were exposed to the high concentrations of PCBs(1 mg/L);③ The expression of BMP-2 and BMP-4 gene declined obviously in the PCB-treated larvae at concentrations 0.125 mg/L and 1.000 mg/L compared with their controls. Conclusion: Embryonic exposure to high levels of PCBs induced developmental deficit in zebrafish skeleton,which suggests the value of monitoring organic contaminant.