Abstract: Improving the wide-temperature operation ability of fiber lasers can effectively enhance the environmental adaptability and operation reliability of fiber lasers under extreme high- and low-temperature conditions. This ensure their stable output under complex working conditions, and provides support for technological innovation and industrial upgrading in related fields. Recently, the National University of Defense Technology achieved a near-single-mode all-fiber laser oscillator that can operate stably within the temperature range of −50 to 50 ℃ by directly pumping with fiber-coupled semiconductor lasers. The output power reached 2 kW, which is the highest output power level of fiber lasers operating in such a wide temperature range reported publicly so far.