Objective To investigate the gene transduction efficiency of lentiviral vector in leukemia cells to provide key basis for leukemia gene therapy. Methods A third-generation self-inactivating(SIN) lentiviral vector system based on human immunodeficiency virus type 1(HIV-1) was used to improve transduction efficiency.The transduction efficiency of the HIV-1-based vector was compared directly with the moloney murine leukemia virus(MLV) SIN vector in human leukemia cell line K562.The expression of green fluorescent protein(GFP) in cells was observed by fluorescence microscopy and flow cytometry(FCM) to detect the percentage of gene trasduction cells.Results The GFP expression in K562 cells was observed qualitatively by fluorescence microscopy.At the same gene transduction conditions,the GFP marker gene expression intensity and GFP positive cells in leukemia cells transduced with HIV vectors were significantly higher than those transduced with MLV vectors.Initial transduction efficiencies were almost 100% for the HIV and less than 40% for the MLV vectors. The transduction efficiency had significant difference between HIV vector group and MLV group(P