Diamond film wafers were prepared by high power DC-plasma jet CVD method. The microstrures and the orientation of grain growth for the diamond film were studied by XRD, OM. SEM and Raman spectroscop. The results showed that grains grew in random orientation. Atom hydrogen etching benefited the nucleation and growth of crystal embryo. Methane concentration has important influence on the preferentially orientated growth of the grains. Upon a low methane concentration, (111) facet of the diamond film grew in preferential orientation, and an octahedron crystal was formed. Finally the optical diamond film with uniform center and edge, high quality was prepared. Adopting high power DC-plasma jet CVD method, the speed of growth of diamond was lower. Meantime, the vacancies and vacancy clusters were also found.