We tried to make blends of polyisobutylene and amorphous polyamide. In order to improve the compatibility of polyamide (PA) with isobutylene (IB), we used liquid-isobutylene resin (LIB) having terminal alkoxysilyl groups and a silane coupling agent (SC) which is reactive to both PA and LIB as a compatibilizer. We first synthesized a reactant of amorphous polyamide (APA) and SC, and by mixing APA/SC reactant and LIB in alcohol, LIB/APA blends were obtained. By SEM observation, the measurement of viscoelastic, the structural analysis and mechanical properties of the blends, it was found that the matrix and the dispersed phase were LIB and APA, respectively, and that a chemical bond was formed between LIB and APA, in the presence of SC. Thus SC played as a good compatibilizer to afford good dispersion of APA phase in LIB matrix.