Objective: To study the efficient expression of GST-Tat protein in Escherichia coli BZ21 (DE3). Methods: HIV-l Tat gene was amplified by PCR from cDNA library of HIV and was inserted into vector of pEGx-KG. The recombinant plasmid was transferred and expressed in E. coli BL21 (DE3). The expressed products were identified by SDS-page and Western-blot. Results: HIV-1 Tat gene was amplified successfully by PCR. The recombinant plasmid was expressed efficiently in E. coli (BL21). SDS-page and Western-blot analyses showed the expressed Tat fusion protein with relative molecular weight was 38.9 kDa. Conclusion: HIV-1 Tat gene can be cloned and GST-Tat fusion protein can be expressed efficiently in E. coli, which may contribute to further research of anti-AIDS.