Objective To develop a method of studying fiber projecting in the spinal cord duiring chicken embryo development.Methods At embryonic incubation 3 day (E3), pCAGGS-green fluorescent protein (GFP) plasmid was injected into the spinal cord using in vivo electroporation.Three days after transfection (E6), GFP-positive embryos were collected under a stereo fluorescence microscope .Subsequently , the spinal cord was separated from the embryos and cut from the roof plate as an open book .After fixed with 4%paraformaldehyde ( PFA) for one hour , the opened spinal cords were used for immunohistochemistry with N-cadherin antibody and with DAPI for nuclei .Finally, the nerve fiber projecting was photographed and analyzed under a fluorescence microscope . Results Based on the opened spinal cord and immunostaining in the cryosection , we observed that the nerve fibers projected across the midline of the floor plate and reached to the sulcus terminalis along the white matter of the contra side .The immunoreaction against N-cadherin indicated that overexpression of GFP has no significant effect on chicken embryonic development .Conclusion A new method to study fiber projecting in the developing chicken spinal cord is established successfully in this study .