Abstract: Objective: To identify the primary promoter of LRP16 gene and explore the possible regulation mechanism of LRP16 gene expression up-regulated by estrogen. Methods: The human LRP16 gene promoter, -213 to -24bp of 5′-flanking DNA fragment （2.6kb）, were sub-cloned and inserted into pGL3-Basic vectors. Then the five constructs pS_7-11 plus two previous constructs pS₅ and pS₆ were transient cotransfection with estrogen receptorα（ERα） gene expression vector in MCF-7 and Hela cells. The relative Luciferase activity induced by 17β-estradiol （β-E2 ） was detected by Luciferase Assay. Results: All constructs can up-regulate the relative luciferase activity in MCF-7 and Hela cells cotransfected with ERα expression vector, and the increased extent in MCF-7 and Hela cells was nearly consistent. The E2-induced transactivation activity conferred by pS₁₀ reach 427 times, was significantly increased than those conferred by pS₅. Conclusion: LRP16 gene expression is induced by E2 via the region of -213 to -24 bp, and the fragment of -213bp to -126bp（pS₁₀ ）may be the primary promoter.