Abstract: The output power of high-power single fiber laser is limited by various physical effects, and it is difficult to achieve a breakthrough in the short term. Coherent beam combination (CBC) of fiber lasers is an effective technical solution to break the power limit of single fiber laser and achieve higher output power. This paper introduces the status quo of CBC research, which mostly uses free-space structure. It is analyzed that the CBC scheme of spatial structure requires complex optical adjustment, and suffers the problem of long-term drifting. The all-fiber coherent beam combination based on all-fiber combining device can enhance the stability and practicability of the combining laser source, and the recent development of CBC in all-fiber format is reviewed in detail. The combining schemes and research status based on fiber coupler, photon lantern, coherent signal combining device and all-fiber device of self-imaging effect are introduced respectively. The main limiting factors and development bottlenecks of different fiber devices are discussed, and the future development prospects are analyzed.