Good quality superconducting YBa2Cu3O7-x (YBCO) thin films have been fabricated on Hastelloy (Ni-Cr-Mo alloys) metallic substrates with CeO2 and BaTiO3 buffer layers in situ by pulsed laser deposition in a multi-target processing chamber. YBCO film with CeO2 single buffer layer shows a T-c of 71.64 K and a grain size less than 0.1 mum. When BaTiO3 is used as a single buffer layer, the grain size of YBCO is observed to be 200 times larger than YBCO/CeO2 and the transition temperature of the film is enhanced by approximately 84 K. The CeO2/BaTiO3 double buffer layer has been adopted to enhance the superconducting properties, which results in an enhancement of the critical temperature and the critical current density by approximately 85 K and 8.4 X 10(4) A/cm(2) at 77 K, respectively, mainly due to the enlargement of the grain size of YBCO film.