The most important and well-studied symbiosis system in agriculture is legume-rhizobia symbiosis. Through BNF associated with rhizobia, legume crops could gain the most of nitrogen required during growth, which minimized the usage of nitrogen fertilizer. The nitrogen utilization efficiency for biologically fixed nitrogen is also higher than the efficiency for industrial fixed nitrogen fertilizers. According to Cheng (2008), twice amount of industrial fixed nitrogen are needed to achieve the effect of biological nitrogen fixed by legume. Besides, Lindemann and Glover (2003) discovered that the presence of nodules seems to be related with high nitrogen fertilizer intake efficiency in common beans. The benefit of BNF is not limited to legume itself, part of the nitrogen fixed through legume-rhizobia symbiotic nitrogen fixation will be allocated into soil, benefiting other species growing around or after legume plants (Walley et al. 1996). It’s been recorded that the rotation with legume crops has been applied since ancient China and Rome (Cheng 2008). Unlike legume, major food crops such as rice and wheat don’t have BNF system. The growing population will reach nine billion by 2050, which will bring big pressure for food production. How to grow enough food in limited land and under climate change would be a challenge for human survival. Legume-rhizobia symbiosis demonstrated a great way for sustainable agriculture. To understand the mechanism of legume-rhizobia BNF and transfer such ability to cereal crops will be promising for dealing with future challenge.