High Nb-containing TiAl alloy (Ti-45Al-8.5Nb-(W, B, Y) (at.%), abbreviated as TAN alloy) was successfully brazed at 1100 °C using Ti-28Ni (wt.%) eutectic brazing alloy. The typical interfacial microstructure was TAN/τ3-Al3Ti2Ni + B2/α2-Ti3Al layer/α2-Ti3Al + δ-Ti2Ni/α2-Ti3Al layer/τ3-Al3Ti2Ni + B2/TAN. The effects of holding time on interfacial microstructure and joining properties of TAN brazed joints were investigated in detail. The results demonstrated that the diffusion of Ni from molten brazing alloy to TAN substrate played an important role in the interfacial microstructure evolution, which resulted in an increase of diffusion zone and a reduction of brazed seam with the prolongation of holding time. Shear test indicated that the maximum shear strength at room temperature and high temperature (600 °C) reached 248.6 MPa and 166.4 MPa respectively when holding time was 15 min. Fracture analyses revealed that brittle fracture preferred to initiate and propagate in the continuous intermetallic layers during shear test.