Narrow linewidth semiconductor laser has been widely used in high-speed coherent optical communication, distributed sensing, lidar and other fields due to its high monochromatic, low frequency noise and high tunability. With the development of high quality factor (Q) optical resonator, silicon optical isomerization integrated chip and other technologies, the narrow linewidth semiconductor laser has experienced revolutionary development in the last decade. The linewidth has been compressed to the order of kHz or even sub-kHz. In this paper, the latest developments of kHz narrow linewidth semiconductor laser are described, and the narrow linewidth lasers with different linewidth compression mechanisms are classified. The influence of optimizing coupling coefficient and reducing external cavity loss on the performance of narrow linewidth laser is discussed. The development trends such as further compressing the line width and improving the output optical power are prospected.