Epoxy resin is a very important matrix resin of resin transfer molding,however,the high viscosity of epoxy resin greatly restricts its application.A preparation method of low viscosity epoxy resin system for the RTM is proposed,and the effects of its every components on the performances have been studied in detail.It is found that this modified epoxy resin system has excellent technological properties,and then the system is characterized.The relationship between its structure and performances are studied.The results show that this resin has a very good high temperature property.