Abstract: Direct diffusion bonding of high Nb containing TiAl alloy(TAN) has been conducted at temperatures of 1000℃～1200℃ for 90min under 25MPa in vacuum. The effect of bonding temperature on interfacial microstructure and mechanical properities of joints was studied and the microstructure of joints was detected by using SEM, EDS, XRD and EBSD. The results indicate that the distinct interface can be seen when the temperature is below 1100℃ and the higher temperature promotes interface disappear; recrystallized grains are observed at bonding interface. The number and size of grains increase with the rise of temperature and a lot of α2 phase appears in the area of recrystallization; the highest average shear strength of 105 MPa was achieved when bonded at the temperature of 1150℃ for 90min under 25MPa.