Ni sulfides layers were formed on the surface of a Ti50Ni50 alloy by reacting sulfur with a Ni film deposited on the alloy, and then microstructures, transformation behavior, shape memory characteristics, superelasticity and electrochemical properties were investigated. When a Ni film deposited on a Ti50Ni50 alloy was annealed under the sulfur pressure of 100kPa at 623K, sulfides layers consisted of NiS and NiS2 were formed. When annealing was made at 648K with annealing time less than 0.9ks, sulfides layers with a mixture of NiS and NiS2 were formed, while only NiS2 was formed when it was made for 1.8ks. When annealing was made at 673K with annealing time longer than 0.9ks, only NiS2 was formed. With raising annealing temperature and prolong annealing time, NiS changed into NiS2 accompanied with a morphological change from a particulate-like to a dense film-like. A Ti50Ni50 alloy with surface NiS2 layer showed the two-stage B2–R–B19′ transformation behavior, the shape memory effect and a partial superelasticity with a superelastic recovery ratio of 78%. NiS2 cathode showed a clear discharge behavior with multivoltage plateaus induced by intermediate reaction products; NiS and Ni3S2. The initial discharge capacity was 743mAhg−1 corresponding to 85% of theoretical capacity and 65% of capacity duration is obtained at 20th discharge.