The phase equilibria related with the liquid phase at 1000℃ in low-Ni side of the Nb-Ni-Ti system have been investigated by SEM, EPMA, XRD and DSC. It has been shown that there exists the liquid phase which could be in equilibrium with the continuous solid solution (Nb,betaTi) and compound TiNi in the low-Ni side of the Nb-Ni-Ti system at 1000℃. The liquid phase field originates from binary Ti-Ni system and extends to the 3.7%Nb (atomic fraction). The solid solubility of Nb in the compound TiNi is about 8.0%. At 1000℃, there are two three-phase fields consisting of Liquid+(Nb,betaTi) TiNi and (Nb,betaTi) TiNi XB in the Nb-Ni-Ti system, XB is the compound with the composition of 34.0Nb-44.9Ni-21.1Ti% and hexagonal structure. The broad two-phase field (Nb,betaTi) TiNi exists between the two three-phase fields. In this two-phase field, the Ni content in the continuous solid solution (Nb,betaTi) is about 3%, but the Ti content varies from 6.6 to 39.9%. The thermo-stability of the compound Ti2Ni has been improved by the solution of Nb atoms, but the Ti2Ni with 3.7%Nb could not exist at 1000℃.