AIM: Constructing plasmid that expresses human plasminogen kringle 5 gene to analyze the gene expression in E.coli. METHODS: The gene of human plasminogen kringle 5 was inserted into plasmid PBV220 EcoRI site by gene manipulation techniques and was transformed to E.coli TGI. The gene expression was observed by SDS-PAGE. RESULTS: Expression vector PBVK5 was constructed, and human plasmingen kringle 5 gene product was obtained at 42℃ induction. CONCLUSLON: Expression product of human plasminogen kringle 5 gene was soluble form of proteins, and the expression amount was 9.8% in E.coli TGI total proteins.