The high-power solid-state laser fiber coupling is researched theoretically and experimentally. The output beam quality of high-power solid-state laser is deteriorated with the increasing laser power. According to the laser beam quality，the minimum core diameter of the transmission fiber and the effective focal length of the coupling lens are calculated. Experiments were done. The optical fiber output power is more than 500 W，and the coupling efficiency is better than 90%. It can meet the needs of scientific research and industry application.