In this study TIG welding was carried out in Ti-15V-3Cr-3Al-3Sn alloy by using Ti-6-4 alloy filler. The effect of two common industrial heat treatments (artificial aging treatment at 593°C/2hr /air cooling or a solution treatment at 788°C/30min/air cooling plus aging at 510°C/8hr/furnance cooling) on the microstructure, mechanical property and corrosion resistance of weldment were investigated. It appears that these post weld heat treatment result in enhanced mechanical property as well as its corrosion resistance. In addition, solution plus aging treatment presents the excellent mechanical property and corrosion resistance. TEM investigation is also carried out to observe the nano size precipitates in heat affected zone (HAZ) and fusion zone (FZ). The possible enhanced mechanisms are discussed.