Transformation behavior of a Ti-43.0Ni-5.0Cu-2.0Fe(at%) alloy has been investigated by means of electrical resistivity measurement, differential scanning calorimetry and X-ray diffraction. The alloy transformed in three-stage during each cooling and heating procedure. That is, the B2-R-B19-1319' on cooling and the B19'-B19-R-B2 on heating.