Abstract: Beam combining of high energy fibre lasers is the research hotspot especially for the directed energy application in recent years, which can overcome the output power lever limits of one single-mode fibre laser, and establish the theoretical foundation for the application of laser weapons with high power and perfect beam quality. Research status of fibre laser incoherent combining and coherent combining were presented. In the section of incoherent combining, the combining principle and combining level of beam overlap and spectral beam combining were introduced. In the section of coherent combining, the key combining apparatus of transmission-type and reflection-type equivalent large aperture laser array output and optical element of single aperture output were analyzed in detail. The advantages and disadvantages and range of application of high power fibre laser beam coherent combining and incoherent combining were compared briefly.