The effect of yttrium on the electrochemical polarization behavior, composition and semiconductor property of passive film in Al-Y glasses have been studied. It was found that the corrosion potential and passive current density are sensitive to the minor variation of yttrium content. The high Y-containing samples possess a homogeneous single layer passive film rich in yttrium. The passive film exhibits a p-type semiconducting behavior and the carrier density tends to be reduced with increasing yttrium due to the formation of YAlO3. Higher yttrium content makes the passive film inert to electron transfer and the metastable pitting are inhibited.