Two epoxylated novolacs based on phenol-formaldehyde and resorcinol-formaldehyde condensation products respectively were synthesized． Both of them contained more than two epoxy groups per molecule．After curing with various curing agents，the deformation under constant lpad and the weight loss at elevated temperatures of the cured resin were measured． It was proved that with an increase in the number of functionality present in the resin，the degree of cross linking was increased． As a consequence，the cured resin showed higher glass transition temperature and smaller deformation in high elastic state．Their high temperature performance was thus better than similar system based on the diglycidyl ether of bisphenol A resin．