Abstract: The wide application of high power fiber laser makes it become a new hotspot in the research of solid state laser. But due to stimulated Raman scattering(SRS) and stimulated Brillouin scattering(SBS) effect, the maximum output power of single fiber is limited, and beam quality becomes worse with the increase of power variation. Method of parallel beam combining of fiber laser because of its poor beams, so that its application is restricted, and coherent beam combination technology can make multiple laser beam coherent superposition, so that the output power can be improved while ensuring good beam quality. In this paper, the design and theoretical calculation of one core, three core, seven core photonic crystal fiber light distribution were conducted, proving that integrated photonic crystal fiber can be very good to achieve coherent beam output, while achieving a high output power and high beam quality of fiber laser.