Abstract: Through the electrophilic addition reaction of —P(O)—H and C=C，a novel phosphorus-containing maleimide phenolic resin was synthesized and used as curing agent for preparing high performance，flame retardant epoxy resins. The structure of the resin was confirmed with FTIR and elemental analysis. Thermal properties and thermal degradation behavior of the thermosetted resin was investigated by using differential scanning calorimetry （DSC） and thermogravimetric analysis （TGA）. High glass transition temperature （145.4℃） and high char yield （700℃ 49.5%） were observed for the P-PMF/CNE cured resins. A sample containing 1.48%（mass ratio） phosphorus had limiting oxygen index values of 33.3. The developed resin may be used potentially as a “green” curing agent in electronic fields.