The microstructures and the mechanical properties of two TA15 titanium alloy ring forgings rolled in (α+β)phase field were compared. The processing features and the effect of the microstructure on the mechanical properties were analyzed. The results show that the duplex microstructures with the equiaxed primary β phase on the transformed α phase matrix are obtained by (α+β)phase field rolling. The volume fraction of the equiaxed primary α phase and the transformed β phase, as well as the morphology of secondary α phase in the transformed β phase have great effects on the mechanical properties. The increase of the volume fraction of the primary equiaxed α phase improves the tensile ductile and impact properties, but decreases the fracture toughness, stress rupture and creep properties. The decrease of the volume fraction of the transformed β phases and the sphericized secondary α phases in the transformed β microstructure decrease the crack-propagation resistance and the high cycle fatigue property.