The aim of this work was to study the viscosity and curing properties of epoxy resin system, in order to provide a theoretical basis for manufacturing launch box using RTM process. The dynamic viscosity and static viscosity of the E-51epoxy resin system were tested by rotational viscometer. The curing behavior of the resin system was studied using the non-isothermal DSC method and Flat knife method. The viscosity of the resin system was still less than 1000 mPa·s after 70 min at 60~80 ℃, which met the process requirements. And it was deduced that the curing temperature parameter was 60, 125 and 180 ℃ respectively, as well as the relationship equation of gel time and temperature. The temperature range 60~80 ℃ could be used as the operating range for RTM process to manufacture launch box. The recommended curing process of system was heat curing 3.5, 2 and 1 h at 60,90 and 125 ℃respectively, post-treatment process for the next 1h at 180 ℃.