Abstract: The biosynthesis and metabolic pathways of isoflavones were reviewed， the latest research progress on their functions in symbiotic nitrogen fixation between rhizobia and soybeans were summarized， and also their other roles in leguminous plants were introduced，such as disease resistance and stress response. Furthermore，the future research directions were prospected， aiming to use isoflavone research as a breakthrough point to achieve legume crop improvement and “artificial symbiotic nitrogen fixation” in non-leguminous crops through genetic engineering technology. This could fundamentally transform the global dependence on nitrogen fertilizers and promote the sustainable development of green agriculture.