Abstract: Bisphthalonitrile-etherified xylok resin(BPX) was synthesized through nucleophilic replacing reaction between 4-nitro bisphthalonitirle and xylok resin with base as catalyst.The results of rheology test showed that the viscosity of BPX resin was below 400 MPa.s at 165²85℃,indicating that the resin possesses excellent processing capability.DSC curve of BPX resin revealed that the thermal polymerization reaction occurred at 320~420℃with peak temperature of 386.24℃ and exothermic enthalpy of 182.26J/g.BPX resin exhibited excellent thermal stability.The results of TGA showed that 5% weight loss temperature and char yield at 900℃ were about 519℃ and 75% respectively.