The relationship of microstructure evolution with subzero treatment time and number of Inconel 617 alloy was studied. The results indicate that subzero treatment has an obvious influence on the microstructure of Inconel 617 alloy. With the increase in subzero treatment time, the grain size decreases. With the increase in subzero treatment number, the grain size increases gradually, and the high stress is retained at the boundaries of the refined grains. The lattice constant varies inversely with the grain size. The simple and complex carbides of MC, M₆C and M₂₃C₆ are precipitated from the samples after subzero treatment, which leads to the accumulation of dislocations. The geometrically necessary dislocation density of the samples increases after subzero treatment for 24 h, and decreases significantly with two times of subzero treatment for 24 h. In addition, after subzero treatment, the rotated cube texture and rotated copper texture transform to brass texture, P texture and goss texture.