The work aims to study the growth technology of high quality single crystal diamond. X-ray white light topography was used to analyze the change of dislocation density in single crystal diamond on the diamond surface before and after etching processing. Then plasma etching pretreatment technology was adopted to study the effects on crystal diamond by changing the deposition temperature. To characterize the influence of temperature on quality of single crystal diamond, Raman spectra and X-ray rocking curves were used to analyze the change of quality and dislocation density of single crystal diamond and determine the best temperature to deposit the high-quality single crystal diamond. X-ray topography images showed that diamond seeds without surface etching by hydrogen and oxygen plasma had more dislocation density in epitaxial layer due to dislocation or micro cracks caused by surface machining or polishing. Meanwhile, the results of surface etching experiments by hydrogen and oxygen plasma showed that longer etching time was not good all the time. When the single crystal diamond seeds after the etching were tested for epitaxial growth at different temperature, the Raman peaks of single crystal diamond grown after etching were all approximately 1332.5 cm?1 and FWHM (Full width half maximum) were all in the range of 2~3 cm?1. After deposition at 900 ℃, FWHM of X-ray rocking curves was as little as 0.009. Etching single crystal diamond by hydrogen and oxygen microwave plasma for 40 min at 800 ℃ could almost eliminate the dislocation or defects introduced by micromachining or polishing. The single crystal diamond prepared by seeds etched at 900 ℃ had the highest quality and the least dislocation and can meet the preparation requirements on high-quality single crystal diamond.