Objective: To clone the gene encoding Oct4 protein regulating human embryonic germ cell pluripotency and to express it in E.coli(k802). Methods: Total RNA was extracted from gonadal ridges and mesenteries of 4- to 6-week-old human embryos and cDNA amplification was performed by Reverse Transcription-Polymerase Chain Reaction (RT-PCR). The full-length Oct4 cDNA was cloned into prokaryotic expressing vector-pGEX5T and the product was sequenced. PGEXT-oct4 was then expressed in k802 E.coli. Results: One specific band of 1.1 kb was obtained and had 97％ affinity to that reported in GenBank. The protein was successfully expressed,exhibiting a 62 000 band by SDS-PAGE analysis. Conclusion: The full-length Oct4 cDNA has been amplified and cloned,and Oct4 protein is expressed successfully in k802 E.coli. This may be helpful in future studies on pluripotency and differentiation of human embryonic germ cells.