In this study, microwave plasma chemical vapor deposition was used to control the trace impurities for preparing high-quality single-crystal diamond materials, the structural and optical properties of which were comprehensively evaluated. Further, the impurity contents of the crystals were analyzed using ultraviolet (UV)-visible absorption spectroscopy and photoluminescence spectra. The crystal structures and quality of the single crystals exhibiting different qualities were analyzed based on the Raman spectrum, X-ray rocking curve, and X-ray white-light morphology beam. Subsequently, the crystal structures and defects of a single-crystal diamond exhibiting different qualities were evaluated under a polarizing microscope. The obtained high-purity single-crystal diamond contains a few defects and impurities, and its dislocation stress field is uniformly distributed in the aggregate state. The maximum transmittances of single-crystal diamonds with high purity and low-doped nitrogen in the UV visible near-infrared (UV-visible-NIR) band are 71.58% and 71.27%, respectively, which are approximately similar to the theoretical value of transmittance (71.6%) for diamond. In the intrinsic infrared absorption band, the lattice symmetry of high-purity diamond crystals is better, whereas the absorbance is smaller than that of low-concentration nitrogen-doped single-crystal diamonds. The high-quality single-crystal diamond film prepared by controlling the trace impurities is expected to be used as an optical detector probe and an optical window.