Abstract:The construction of stable, feasible and high-yielding plasmid vector has become one of research focuses on recombinant technology. The optimization of plasmid vector is still hindered by the lack of information on plasmid instability as well as information on the host metabolic responses. Therefore, this review highlights the stability of plasmid vector when expressing foreign proteins in E. coli and the possible influence factor for its instability, such as the inherent characteristics of the plasmid and the exogenous gene, influence on the host triggered by recombinant plasmid and other factors. Meanwhile, related solutions were briefly introduced, providing a reference for high-level expression of heterologous proteins in E. coli expression system.