Abstract: Reducing grain loss and waste is a major concern for grain security and environmental sustainability. Through sorting out the concepts of grain loss, grain waste and environmental footprint, this paper will evaluate grain loss rate and loss quantity at front consumption ends, including harvest, storage, processing, and transportation by the systematic review method. Subsequently, the environmental footprint of grain loss is estimated. Results show that the loss rates of wheat, rice, and corn in harvesting are 3.765%, 3.771%, and 2.920%, respectively, while the loss rates of front consumption ends are 11.665%, 12.871%, and 13.320%, respectively. The total loss of three staple grains in 2020 is 77.65 million tons, including 15.660 million tons of wheat, 27.269 million tons of rice, and 34.721 million tons of corn. The average carbon footprint is 20.189 million t CO₂ equivalent (CO₂e), the average blue water footprint is 10.095 billion m³, and the average land footprint is 23.295 million hm². Although the reasons for grain loss are different, there is a common path to reduce loss, which is improving the technological level at front consumption ends. Therefore, this paper suggests updating the level of agricultural machinery and equipment, improving grain storage facilities and conditions, innovating grain processing technologies, and promoting efficient grain transportation equipment.