Using Ti-40mass%Ta-0, -4, -8 and A 12mass%Sn alloys, the effect of Sri addition on phase constitution in the solution treated and quenched state and isochronal heat treatment behavior is studied by electrical resistivity and Vickers hardness measurements and X-ray diffactometry. To confirm shape memory effect of some of these alloys, shape-recovery test was also performed. Orthorhombic martensite, alpha" was identified in Ti-40Sn-0 to 8Sn alloy quenched from 1173K, while beta phase was identified in STQed Ti-40Ta-12Sn alloy. On isochronal heat treatment, increases of resistivity at LN and resistivity ratio were observed in only 8Sn alloy, because these increases are due to reverse-transformation of alpha" to beta phase. From result of shape recovery test, shape memory effect was observed in Ti-40Ta-4 and 8Sn alloys.