With the widespread application of rigid polyurethane foams in various engineering fields,their flameretardant properties are receiving attention increasingly.This article introduces the development of the research of flame-retardant technique by using polyurethane foams at home and abroad.It analyzes the flame-retardant mechanism by using polyurethane foams and the trend of the research of flame-retardant methods.The paper mainly explains the flame-retardant effect by the combined use of two flame-retardant methods: by the structural modification of the polyurethane molecules and adding compound flame-retardant agent,the oxygen index of the polyurethane foams can be made to reach the national flame-resisting standard.The paper also envisages the prospect of flame-retardant technique by using polyurethane foams.