Abstract: [Abstract]We had selected the earlier embryos of generic hybridization of chicken and quail (2.75-5.0 d),designed primers from quail Wpkci and β- actin genes,and used RT-PCR method to establish a way to identify the sex of earlier embryos of hybridization of the chicken(♂) and quail(♀).Amplified cDNA of quails of known sex and hybridizations’embryos of unknown sex with Wpkci primers ,we had acquired two particular segments of 402 bp and 296 bp from the female embryos, but none from the male embryos. In order to verify credibility and stability of this system deeply, we had acquired three particular segments of 490 bp,402bp,296bp from the female embryos with multi-ply PCR, but only acquired the internal standard segment of 490 bp from male embryos.Based on the optimization of the key factors of the experiment, we had established a simple,fast,credible and stable method to identify the sex of earlier hybridizations 'embryos.