We immersed micropores-formed glass fiber reinforced polyamide MXD6 (GFR-MXD6) in SBF and precipitated apatite nuclei in the pores of the substrate by raising both the pH and the temperature of SBF and obtained bioactive GFR-MXD6. By immersing in SBF, hydroxyapatite formation was induced by the apatite nuclei in the pores and grew to the surface of the substrate. High adhesive strength between the formed hydroxyapatite and the substrate was obtained by a mechanical interlocking effect.