High-power erbium-ytterbium codoped fiber lasers have been widely applied to optical fiber communication, lidar, satellite remote sensing, and precision measurement owing to its “eye safety” and low loss characteristics in both optical fibers and atmosphere. This study briefly introduces the developments of the erbium-ytterbium codoped fiber and associated laser system and emphatically expounds the latest progress in research on erbium-ytterbium codoped fiber lasers with high power and narrow linewidth. Additionally, we analyzes factors which restrict the increase of power of the erbium-ytterbium codoped fiber laser. In view of ytterbium-band amplified spontaneous emissions and optical fiber thermal effects, optical fiber and laser system structures are optimized to realize an erbium-ytterbium codoped fiber laser with higher output power.