To repair the titanium alloy impeller for airplane starter, laser melting deposited Ti-6Al-3.5Mo-1.8Zr-0.23Si(TC11) titanium alloys, as well as the microstructure and properties of the interface, are investigated. The results indicate that the deposited TC11 titanium alloys and the interfacial re-melted layer present a typical Widmansttten structure and the heat affected zone (HAZ) within the substrate changes gradually from Widmansttten to duplex microstructure. Compared to the interface transition zone and the substrate, the as-deposited TC11 alloy possesses higher tensile strength and lower ductility. The damaged impeller blades are repaired by laser melting deposition in a point-by-point way. After machining and checking, the repaired impeller passes the over speed test and comes into real use.