The effects of different heat treatment on the microstructure evolution and properties of Ti650 alloy plate were studied. The results show that：Ti650 alloy plate is sensitive to the change of solution temperature. The primary α phase dissolution occurs with the increase of solution temperature, and the secondary α phase is small in size and staggered, which increases the resistance of dislocation movement, increases the strength and decreases the plasticity of the plate. Increasing aging temperature, secondary α size increases from fine needle like to coarse and becomes long or short layered, arranged in staggered bundles with different orientations, resulting in a significant increase in the plasticity of the sheet and an appropriate decrease in strength. Under the condition of aging temperature of 700 ℃ and aging time of 2.5-6 hours, the effect of aging time on the microstructure and properties of the sheet is relatively small. The nucleation, precipitation and growth of secondary α phase are affected by different solution cooling rates. The dimples in the fiber region are small and shallow with good plasticity when the cooling rate is low (furnace cooling); When the cooling rate is fast (air cooling, water cooling), the ductile dimples are large and deep, and some tearing edges can be observed, resulting in poor plasticity.