High-power semiconductor lasers operating at a wavelength of 800 nm are one of the preferred laser sources for long-distance illumination. However, owing to poor beam quality and brightness, it is difficult for 800-nm semiconductor lasers to transmit over long distances. Therefore, it is essential to improve the beam quality and brightness. For spectral beam combining method, the output power and brightness are improved while preserving the beam quality of a laser unit. Based on this method, a high-power laser source comprising 10 800-nm laser arrays is developed by optimizing the spectral width and the combining structure according to the gain spectra of laser bars, with a continuous power of 363.5 W, beam quality of 4.17 mm·mrad, brightness of 212 MW/(cm 2·sr), and electro-optic conversion efficiency of 40%. Through further structural optimization and polarization coupling, a kW-class high-power 800-nm semiconductor laser can be obtained, providing a high-performance laser source for long-distance laser illumination.