Abstract: A new epoxy composite system was developed, being suitable for the case of inner pressure vesselswith PE as inner liner for water t reatment with wet fiber-inding. The examinations of viscosity, mechanical properties and blast were done. The results show that the modified epoxy composite system has longer gel time andlower viscosity at room temperature, and it can gel and cure at lower temperature. So the composite vessel has goodmechanical properties and fatigue property, higher blast st rength and lower cost, being capable of water t reatmentwith wet fiber-winding.