Poly(benzoaxazoles) (PBO) are a class of high, temperature organic polymers which have low dielectric constant. The interfacial characteristics of PBO/copper system have been investigated. PBO films on copper substrate were prepared by thermal conversion from poly(hydroxyamide) (PHA). PHA was synthesized by the low temperature, condensation reaction of 3,3'-dihydroxybenzidine and isophthaloyl chloride in DMAc. PHA film on the copper substrate was converted to PBO by heating at 350degreesC. DSC, TGA, XPS, and lap-shear test were employed to characterize both PHA/copper and PBO/copper systems. The XPS results revealed that the polar groups in PHA and the heterocyclic ring in PBO had special interactions with copper at the surface. The adhesive strength of PBO/Cu was slightly greater than that of PHA/Cu system. The dielectric constant of PBO film was about 3.1 and showed no changes with frequency.