In recent years, diabetes has become a public health problem troubling all mankind. Studies have shown that diabetes has a significant correlation with the Glycemic Index (GI). Grain is the main dietary source of Chinese and is closely related to human health. The glycemic index of cereals is influenced by a number of factors, including its basic components and processing methods. In this review, factors, mechanisms affecting the glycemic index of cereals as well as the national and international studies on advances in low GI cereals in recent years were introduced, so as to provide reference and assistance for the dietary choices of patients with high glucose and the research and development of low-GI foods.