Abstract: The narrow temperature control range and stress?plateau hindrance limit displacement control in NiTi shape memory alloy alloys. To address these issues, the layered NiTiNb/NiTi materials are designed and prepared by spark plasma sintering. Their phase transformation characteristics, mechanical responses, and strain evolution behaviors are systematically investigated. The results demonstrate that spark plasma sintering achieves robust interfacial bonding between the NiTi and NiTiNb layers while effectively restricting excessive elemental interdiffusion across the interface. The engineered layered architecture markedly expands the transformation-temperature window to 165.2 K, which is significantly higher than those of monolithic NiTi (87 K) and NiTiNb (99.5 K). Furthermore, the conventional stress plateau is converted into a quasi-linear superelastic response, accompanied by a minimal residual strain of 0.08% and a high energy dissipation capacity of 3.8 MJ m-3. Digital image correlation analysis reveals that the layered configuration regulates strain transfer during forward and reverse martensitic transformations, resulting in layer-dependent strain evolution and enhanced shape memory performance.