The effects of slab microstructure type and heat treatment on mircrostructure and properties of Ti6321 alloy were studied by means of mechanical properties test,OM and SEM analysis. The results show that slab microstructure type of Ti6321 alloy has a significant effect on the microstructure and properties of the rolling sheet. By the same rolling process, that is, the first fire: 980℃ start rolling, finish rolling temperature 800℃, ε=70%, and the second fire: 995℃ start rolling, finish rolling temperature 800℃, ε=50%,equiaxed slabs form bimodal slabs, and Westernized slabs form equiaxed slabs. After annealing below (α+β)/β phase transformation point, the longitudinal and transverse yield strength and tensile strength of the plate made of equiaxed slab are higher than those of the corresponding direction of the plate made of Widmanstatten slab, while the elongation and impact energy are opposite. With the increase of annealing temperature, the yield strength and tensile strength of the sheets prepared with different slab structures decrease slightly, while the impact energy increases sharply. When annealed above (α+β)/β transformation point, the tensile properties and impact work of the two alloys decreased significantly. During the annealing process in the α+β two-phase zone, the sensitivity of the initial α phase to temperature is higher than that to the holding time of annealing. With the increase of temperature, the content of primary α phase decreases sharply, while the content of secondary flake α phase increases obviously. The suitable annealing process range of Ti6321 alloy is (940～980)℃/(2～3) h.