Tensile, flexural and water resistance properties of four kinds of epoxy resin systems, i.e. CYD-128/THPA/DMP-30 (CTD), TDE-85/THPA/DMP-30 (TTD), CYD-128/IPDA (CI) and TDE-85/IPDA (TI) were investigated. The influences of the epoxy resin types, curing agent types and molecular structures on the properties of the epoxy matrixes were discussed. The results show that, cured with a same curing agent, TDE-85epoxy resin (with ester groups) system exhibits higher flexural strength and Young's modulus than CYD-128 (without ester groups) system. The brittleness order of the four epoxy matrixes is TI>TTD≈CTD>CI. As CTD and CI have less content of polarity groups, such as ester and amine, seawater absorption of CTD and CI is smaller than that of TTD and TI. After seawater immersion, part of the ester groups hydrolyzes and the matrix becomes more brittle. As a result, the tensile and flexural strength of the matrixes are decreased significantly. CTD system recovers about 92% of the original tensile strength after drying processing.