The effect of solid solution temperature (aging at 700℃) in two phase field (α+β) on microstructure and properties of IMI834 titanium alloy forging was studied. Optical and transmission electron microscopy were employed to analyze the microstructure. The tensile properties at room and 600℃ and thermal stability and creep rupture property at 600℃ were tested. The results show that with the increase of solid solution temperature, the content of primary α phase decrease and the size of transformed β and secondary α colonies increase slightly, the tensile plasticity decrease slightly at room and 600℃, the creep rupture property is significantly improved at 600℃. The thermal stability of samples by heat treatment with solid solution in the range of 1000–1030℃ is basically equivalent. The effect of solid solution temperature on properties is closely to element distribution and the size of transformed β and secondary α colonies.