20 centimeters. According to official website, a college student, the dormitory beds in beijing university of chemical technology are made according to the regulations in GBT3328 to 1997 "Main Dimensions of Furniture Beds". The "Regulations" stipulate that the height of the safety guardrail of the dormitory bed should be greater than or equal to 20 cm, and the gap between the guardrail and the bedside should be 50 to 60 cm.