In this paper, the microwave plasma chemical vapor deposition method was investigated to produce homoepitaxial single-crystal diamond by the growth of a diamond seed. The effects of substrate temperature on diamond growth were studied via characterizations of Raman spectroscopy, scanning electron microscope and optical microscope. The results show that substrate temperature is an important factor that affects the growth rate, mode and defects. Within a certain temperature range, the growth rate of diamond increases with the substrate temperature rising. Meanwhile, the growth mode also turns into step flow mode instead of hillock mode. The edge of CVD diamond layer is prone to producing crystalline defects such as twin crystals when the growth thickness of single crystal diamond exceeds 1 mm. Results by Raman spectroscopy demonstrat that single-crystal diamondobtained by the microwave plasma chemical vapor deposition method exhibits better quality than conventional high temperature and high pressure methods.