Abstract: People’s awareness about nutrition and health is increasing in the world. Plant-based foods, especially medicine-food homologous plants, have been received great attention in recent years, and the main active substances included saponins, flavonoids, polysaccharides and volatile oils. As a starter culture in the traditional and modern fermentation industry, lactic acid bacteria are inherently beneficial microorganisms in the human intestinal tract, and exhibit good biotransformation effects and health benefits. Therefore, lactic acid bacteria with high-safety are selected to ferment and transform medicine-food homologous plant to produce more active substances and improve functional efficacy, which becomes one of the research hotspots. In this paper, the biotransformation effect of lactic acid bacteria on the saponins, flavonoids and polysaccharides in medicine-food homologous plants are mainly discussed and reviewed from the aspects of biotransformation effect and mechanism. This review would provide ideas for the research and product development of medicine-food homologous plants biotransformed by lactic acid bacteria.