Abstract: Diamond films were deposited by microwave plasma chemistry vapor deposition method using CO₂/CH₄gas mixtures without supplying additional hydrogen gas.In order to explore the best growth conditions of diamond film,We have a study about the effects of different CO₂ flow on the growth of the diamond films.The surface morphologies and cross-section view were characterized by scanning electron microscopy.The qualities and crystal structure were analyzed by Raman spectroscopy and X-ray diffraction.The results show that the diamond films can be obtained within a certain range of CO₂ flow rate,which had great influence on the surface morphology,with the CH₄was 50 mL/min.The high quality and orientation of the diamond film was deposited under the condition of CO₂/CH₄=30:50,with the growth rate reach 3.4 μm/h.