Chemical vapor deposition (CVD) single crystal diamond possess lots of excellent physical and chemical properties, and the large production of the CVD single crystal diamond is a hot issue in the growth and the industrial production of CVD single crystal diamond. The work aims to study the homoepitaxial growth of single crystal diamond in high power microwave plasma environment, in order to optimize the plasma environment for the growth of single crystal diamond in bulk. The 915 MHz-MPCVD device independently developed by the laboratory was adopted to study the uniform growth of CVD single crystal diamond in the high power microwave plasma environment with 15-37 kW microwave. The morphology and quality of the grown single crystal diamond were characterized by optical microscope and Raman spectroscopy. The high power microwave plasma environment was diagnosed by plasma emission spectrum. The results indicated that when the methane concentration was 5% and the microwave power was 15 kW, the size of the plasma ball was too small to cover the substrate platform with the diameter of 150 mm completely. When the microwave power was increased to 37 kW from 28 kW and the methane concentration was also kept at 5%, the energy distribution range of plasma was enlarged to some extent although the scale of the plasma size could not be observed by naked eyes. The substrate platform with the diameter of 150 mm was entirely immersed in the plasma ball which was confirmed by the results of the plasma emission spectrum. Meanwhile, the plasma emission spectrum recorded from the center to the edge regions in the plasma also indicated that increase of the microwave power led to more uniform energy distribution of activated groups within a certain range and also implied that the intensity of microwave electromagnetic field distributed in the different areas of the substrate platform was enhanced with the increase of the microwave power and the substrate temperature. When the microwave power was increased from 28 kW to 37 kW, the better step growth condition could be easier obtained for the grown single crystal diamond distributed in different regions of the substrate. Besides, the increase of the microwave power not only increased the substrate temperature and decreased the variation of the temperature among the single crystal diamond substrates, but also increased the growth rate of the single crystal diamond located at different regions of the substrate platform. In the high microwave power plasma environment, the quality of the grown single crystal diamond is improved obviously, which is attributable to the increase of the activated groups generated in the plasma, because these groups are beneficial to the improving of the quality and growth rate of the single crystal diamond, such as C2 and [H]. Based on the results, the batch growth of 57 single crystal diamond is realized under the condition of the microwave power of 35 kW, the methane concentration of 5% and the substrate temperature of about 950 ℃ and the formation of polycrystalline impurities can also be effectively inhibited in this plasma environment.