Abstract: At present, the operating temperature range of fiber lasers is generally narrow, and if the operating temperature range of lasers can be extended, they are expected to be applied in more environments and fields. Recently, the all-fiber oscillator scheme pumped by an air-cooled fiber coupled semiconductor laser (LD) at the National University of Defense Technology has achieved a laser output of 1 kW in the ultra-wide temperature range of −50～50 ℃. By optimizing the system design, the output power of the laser with wide temperature operation is expected to be further improved.