For China with large population，high resource rigidity，“antenatal” and “middle birth” factors，the food “postpartum” diet is of great value for China。As the last link of grain postpartum，sales plays an important role in grain saving。This paper takes 1662 grain sellers in 51 regions in 9 provinces of China as the empirical research object：the main factors that may affect the loss of grain in the sales link are analyzed and summarized，and the decision experiment analysis method based on fuzzy set theory is applied，systematically analyzed the relationship between the food loss factors of the seller in the sales link，and identified hinge influence factor。The results show that，the age of the grain seller、equipment input level、grain storage conditions，the supply and management level of public facilities in the market，the strength of the government’s policy to support the grain market is the five key factors that affect the loss of grain in the sales link，and accordingly policy recommendations were put forward。