<p>The effect of solution treatment on the microstructure and stress-rupture property of a Ni₃Al-based single-crystal superalloy was investigated. The solution treatment temperature is lower or higher than the dissolution temperature of γ/γ′ eutectic phase (<i>T</i>_eut) which has a significant effect on the microstructure. When it is slightly below the <i>T</i>_eut, the γ/γ′ eutectic coarsened and aggregated to form a large petal-like shape. This process caused non-γ′-phase forming elements to diffuse to the ID region, and the γ/γ′ eutectic phase acted as an obstacle hindering the diffusion of these elements, exacerbating the segregation degree of these elements. On the contrary, the γ/γ′ eutectic phases were eliminated, and the segregation degree of alloying elements reduced when the temperature was higher than <i>T</i>_eut. Besides, the deformation inhomogeneity due to the differences in γ′ particle size in ID and dendritic core area for the former regime, γ/γ′ eutectic phase as a weak position decreased the stress-rupture life at 1100 °C/137 MPa. However, the stress-rupture life is nearly twice times that of former when the sample is treated with the later regime, and it is greater than VKNA-25 alloy. This study guides the design of solution heat treatment for Ni₃Al-based single-crystal superalloys.</p>