Poly methyl methacrylate(PMMA) with mar resistant or poly ethtylene(PE) substrates were surface-treated by applying plasma discharge or alkaline solution. Ceramic thin film comprised of silicon oxide, titanium oxide and zirconium oxide was formed on these surface treated substrates respectively from an aqueous solution, and after the formation of ceramic thin film, titanium oxide thin film was also coated on them from aqueous solution at ordinary temperature and pressure. The thin film coated polymer material was tested in mechanical property. The thin film was hard and the adhesion strength to the organic polymer substrate was very high. The substrate was soaked in SBF and apatite was formed on the substrate. This method is promising for developing hard and soft tissue implants with various mechanical properties as well as high bioactivity.