4,4′-(Phenylene-phenyl-p-dioxo)-bis(l,8-naphthalenedicarboxylic)dianhydride(PPOBNDA) with a phenyl substituent and two ether linkages was synthesized by nucleophilic substitution from 4-bromo-1,8-naphthalene dicarboxylic anhydride and Phenylhydroquinone.A polynaphthalimide(PNI) was synthesized from PPOBNDA and 4,4′-ODA via one-step polycondensation.The obtained polynaphthalimide show excellent solubility in organic solvents,and its film caste from m-cresol solution exhibited good mechanical property,high thermal stability and hydrolysis stability.