It is important that the regulation of the expression level and expression time of a target gene in gene therapy and study the gene function. Constitutive or inappropriate expression of the genes with traditional expression system may interfere with the effect of the gene therapy，even may lead to lethal side effect. Inducible expression systems can be used to regulate the expression level of genes of interest in appropriate time according to the aim of the experiments. Up to date, several inducible expression systems have been established and become the potent tools for gene therapy and studying the function of genes of interest. One of the most promising regulatory systems is the mifepristone-regulated system, which has much lower basal transcriptional activity and high inducibility. Recent developments in system design and application was reviewed in this article.