In recent years, with the rapid development of coherent detection technology, single frequency laser has received great attention. The distributed feedback fiber laser has the characteristics of both intrinsic single longitudinal mode and highly sensitive vibration string structure. It has important application value in the field of low noise single frequency light source and fiber laser sensing technology. Based on the application requirements, this paper summarizes the related research achievements of distributed feedback fiber laser in narrow line width light source and fiber laser sensor technology. According to the different requirements of frequency response characteristics of distributed feedback fiber laser in application, the research progress of related technologies is introduced. Finally, the applicability of different distributed feedback fiber laser frequency response processing methods is compared. The future application prospect of distributed feedback fiber laser is also prospected.