NiO/Pd epitaxial superlattices were successfully grown by a reactive evaporation method and their structures were studied by various X-ray diffraction (XRD) methods. We prepared (111) oriented films and (100) oriented films on alpha -Al2O3(00.1) and MgO(100) substrates, respectively. The XRD patterns of 2 theta/theta scans were analyzed by an extended step model calculation. In-plane alignment was investigated by pole figure method and reciprocal space mapping. The specimens can be epitaxially grown up to a certain thickness of the NiO layer t(NiO) [t(NiO) less than or equal to 20 Angstrom for (111) oriented film and t(NiO) less than or equal to 10 Angstrom for (100) oriented film] with the lattice shrinking of the NiO of approximately 10%. On the other hand, those beyond the critical thickness have texture structure with the lattice spacing of bulk NiO.