Abstract: The disclosure discloses a nutritional cereal-based food with low glycemic load and processing method thereof, and belongs to the technical field of processing of healthy foods. According to the disclosure, bulk grain crops are used as raw materials and mixed with a natural plant extract with the content of 3-deoxyanthocyanidin more than 3 mg/100 g and a sulfur-rich plant or animal protein, so that in-situ encapsulation of starch granules is achieved through an interaction of a sulfur-containing protein and 3-deoxyanthocyanidin, and a grain-source nutritional food for special dietary uses with low GI. According to the method of the disclosure, not only is the process environmentally friendly, operation procedures are simple, but also slow release of blood glucose after a meal is achieved by using the product, and the product can be used as a meal replacement food for people with abnormal glucose metabolism and the like.