The polycondensation of p-phenylenediamine and terephtha]oyl chloride in amide solvent system has been studied．In order to obtain high molecular weight poly (1，4-phenyleneterephthalamide) (PPTA)，the solvation of PPTA with the solvents and the competitive side reaction of the solvents with terephthaloyl chloride in amide-salt system were investigated．We can observed from NMR data．the proton resonance of the amide group of these model compounds shifts markedly to lower field due to the effect of solvation．The magnitude of these shifts depends on the kind of solvent and the concentration of the salt used．DMAe and NMP are the solvents which react with terephthaloyl chloride comptitively in the polyrcondensation proeess．