Transformation behavior and superelastic behavior of Ti-Ni-Cu alloys with various Cu content has been investigated by means of electrical resistivity measurement, X-ray diffraction, tensile test and transmission electron microscopy. Two types of heat treatment are given to the specimens : i) Solutions treatment. ii) thermo-mechanical treatment. The transformation sequence in solution treated Ti-Ni-Cu Alloys substituted by Cu for Ni up to 5at.% occurs to B2◎B19` and it proceeds in two stages by addition of 10at.%Cu, i. e, B2◎B19◎B19`. Also, it has been found that Ti-30Ni-20Cu alloy transformed in one stage : B2◎B19. The thermo-mechanically treated Ti-47Ni-3Cu alloy transformed in two stages : B2◎rhomboheral phase◎B19`, while transformation sequence in Ti-45Ni-5Cu and Ti-40Ni-l0Cu alloy transformed as same as solution treated specimens. The critical stress for inducing slip deformation in solution treated and thermo-mechanically treated Ti-40Ni-l0Cu alloy is about 90㎫ and 320㎫ respectively.