Abstract: The epitaxial CVD diamond growth on different substrates by home-made microwave plasma CVD reactor with 5 kW are mainly studied in the paper. The HPHT diamond,CVD hetero-epitaxial diamond and natural type Ia diamond samples are used as the substrates. The relationship with growth conditions such as the different concentration of CH₄ and substrate temperature are analysed,and the surface morphology of the grown CVD diamond is also characterized by the scanning electron microscopy(SEM). The results show that the surface of epitaxial CVD diamond is not smooth due to the defects of HPHT diamond seed. The textured surface is also found that it is difficult to control the growth of the stage of nucleation density by using CVD hetero-epitaxial diamond seed. The natural type Ia diamond could be as an ideal seed for CVD diamond growth with the smooth and perfect surface. The rate of epitaxial CVD diamond growth is about 70.0 μm/h when the concentration of CH₄ is about 10% and the substrate temperature is 1 020℃.