Glucose transporter type 1 deficiency syndrome is a rare neurometabolic disorder caused by mutations of the solute carrier family 2 facilitated glucose transporter member 1 (SLC2A1) gene, characterized by complex manifestations including early onset epilepsy, motor and mental retardation, and movement disorders and so on. Ketogenic-diet is most suitable therapy and should be commenced as early as possible because timing the initiation of the diet may prevent seizure, movement disorder, and cognitive impairment. This review aims to improve the clinicians′ understanding of glucose transporter type 1 deficiency syndrome to ensure the diagnosis as early as possible.