China's energy security situation is increasingly severe. There are many challenges and opportunities in the energy development sector. Bio—fuel has much superiority: abundant resources, product diversification, recycling and increasing rural income. Speeding up bio—fuel development should be a strategic direction for China. In this study we evaluate the relationship between bio—energy utilization and food security using the grey relational analysis method. The results show that China' s biomass energy development has caused little negative impact on food security as determined by agricultural production. However, that does not mean China's bio—energy can develop in an unrestricted way. Developing bio—energy requires the consideration of many factors, including large investment in the short term and fierce competition from biomass supply.