Abstract: The characteristics of the cast microstructure of M4761 single crystal superalloy after pouring and the evolution of the recrystallization microstructure of M4761 single crystal alloy at different ballast and different solution temperatures were investigated.The results show that there are obvious differences in microstructure between M4761 dendrite and M4761 dendrite due to the existence of solidification segregation. The γ' size of the dendrites is smaller than that between the dendrites. The depth of M4761 recrystallization layer increases with increasing temperature and load. When the solution temperature is below 1220 ℃, the depth of recrystallization layer increases slowly. Close to the γ' phase dissolution temperature (about 1220 ℃), the increasing rate of recrystallization depth is accelerated.The γ'phase is enriched and the size is large at recrystallization grain boundaries.From the indentation surface to the recrystallized grain boundary, the size of the γ' phase changes from small to large. From grain boundary to alloy interior matrix, the γ' phase is in uniform distribution.When the solid solution temperature is high, the γ'phase passivation has a spherical morphology.