The effects of high magnetic field on the microstructure evolution of non-equilibrium solidified Cu80Co20 alloy have been investigated by glass fluxing combined with cyclic superheating and cooling method in a superconducting magnet. Results show that both the undercooling and magnetic field can affect the microstructure of Cu80Co20 alloy. The size of Co-rich phase increases with the enlarged undercooling. The Co-rich particles are elongated along the direction of 6 T magnetic field while these granules become more dispersed perpendicular to the direction of 6 T magnetic field. Moreover, the volume fraction of Co-rich phases perpendicular to the 6 T magnetic field reduces significantly.