Polyazomethines(PAM-n, n=6 and 12) were syntheized by the polycondensation reaction of monomer containing azomethine unit and α,ω-dichloroalkane in the presence of a phase transfer catalyst. The monomer containing azomethine unit was prepared by addition of 1,5-naphthalenediamine to 2,4-dihydroxybenzaldehyde in the presence of glacial acetic acid. The PAM-ns show a higher thermal stability than the corresponding the PET-ns. The length of the flexible spacer have less influence on the thermal stability of the PAM-n.