Diamond films with high quality were successfully deposited using a novel growth method-two-step growth technique-in hot filament chemical vapor deposition (CVD) chamber. The characterization of diamond films were investigated by scanning electron microscopy and Raman scattering, which show noticeable improvement in quality of diamond films. The high surface resistivity of diamond films was also investigated. It suggests that the decreasing of activated carbon concentration near the substrate surface and the increasing of secondary nucleation density of diamond are responsible for the well-behaved diamond film growth. In addition, the thermal stability of the diamond layer surface is also beneficial to the growth of the diamond film.