TC8M-1 titanium alloy was the newly developed hot strength and long life high temperature titanium alloy, which the highest serviceability temperature can be reached at 450 °C. The effect of heat treatment process on microstructure and mechanical properties of TC8M-1 titanium alloy was researched by using solution and aging treatment at different temperatures. The results show that the content of equiaxed primary α phase decreases gradually and the transformed β structure becomes coarse with the increasing of solution temperature. Meanwhile, the equiaxed microstructure transforms into duplex microstructure. Therefore, the room temperature strength presents the decrease trend. However, the content of equiaxed primary α phase changes little with the increasing of aging temperature. The stretch strength at room temperature drops a little, but the ductility increases slightly. After heat treatment at 920 °C/2h, AC+580 °C/1h, AC, the TC8M-1 titanium alloy can be obtain the optimum combination of strength with plasticity.