The phase equilibria related to liquid phase in low-Ni side of Nb-Ni-Ti system at 1100 ℃ were investigated through scanning electron microscope (SEM),electron probe micro-analyzer (EPMA),X-ray diffraction (XRD) and differential scanning calorimetry (DSC).The results show that there exists liquid phase in equilibrium with continuous solid solution (Nb,βTi) and compound TiNi in low-Ni side of Nb-Ni-Ti system at 1100 ℃.The liquid phase region originates from low-Ni side of binary Ti-Ni system and extends to 9.4 at％ Nb in isothermal section of Nb-Ni-Ti phase diagram.The solid solubility of Nb in binary compound TiNi is about 10.6 at％.At 1100 ℃,there exist two three-phase regions consisting of liquid+(Nb,βTi)+TiNi and (Nb,βTi)+TiNi+XB in Nb-Ni-Ti system,where XB is the compound with hexagonal structure and composition of 32.8Nb-44.5Ni-22.7Ti.The wide two-phase region (Nb,βTi)+TiNi exists between these two three-phase regions.In this two-phase region,Ti content in continuous solid solution (Nb,βTi) varies from 6.6 at％ to 25.7 at％,but Ni content is almost the same,which is about 4.0 at％.The eutectic transformation L←→(Nb,βTi)+TiNi takes place at about 1138 ℃ in Nb-Ni-Ti ternary system.