Ti90 alloy is a new near-α titanium alloy with the properties of high strength,high toughness,good resistance to corrosion,outstanding process ability and so on,independently developed in China. Based on Ti90 alloy,an optimized alloy with the nominal composition of Ti-5. 5 Al-4. 0 Zr-1. 0 Sn-0. 3 Mo-1. 0 Nb was obtained by our research group. The microstructures and mechanical properties of optimized alloy and Ti90 alloy were investigated by means of X-ray diffraction( XRD),optical microscope,electron probe micro analyzer( EPMA),electronic universal testing machine and electrochemical workstation. The optimized alloy exhibits typical widmannstatten structures with basketweave characteristic; the prior-β grain boundary and α cluster can be clearly observed; the retained β phase can also be found between lamellar α phase. Compared with Ti90 alloy,optimized alloy has apparently improved compressive yield strength,fracture toughness and a better electrochemical corrosion resistance,with its ultimate strain enhanced slightly.