The composition of oxide film of Zr_(55)Cu_(30)Ni_5Al_(10) bulk metallic glass was identified by X-ray photoelectron spectroscopy.In addition,the relatively sound joints of bulk metallic glass without macroscopic deformation were obtained by removing the oxide film before diffusion bonding.The joint interfaces were observed by scanning electron microscopy and atomic force microscopy.The hardness of joints near the interface was higher than that far away from the interface,which is attributed to the difference of structural relaxation.According to the result of micro-focused X-ray diffractometry and transmission electron microscopy,the joints retained the amorphous structure when the holding time is less than 20 min.The surface area fraction of oxide film on the interface of joints was detected by ultrasonic inspection.Moreover,the surface area fraction of oxide film is in excellent agreement with the theoretical value calculated by shear strength.The result indicated that surface oxide film is the dominant barrier on the diffusion bonding of bulk metallic glass rather than low atomic diffusion coefficient. The composition of oxide film of Zr_ (55) Cu_ (30) Ni_5Al_ (10) bulk metallic glass was identified by X-ray photoelectron spectroscopy. Addition, the relatively sound joints of bulk metallic glass without macroscopic deformation were obtained by removing the oxide film before diffusion bonding. joint joints were observed by scanning electron microscopy and atomic force microscopy. hardness of joints near the interface was higher than that far away from the interface, which is attributed to the difference of structural relaxation. According to the result of micro-focused X-ray diffractometry and transmission electron microscopy, the joints retained the amorphous structure when the holding time is less than 20 min. The surface area fraction of oxide film on the interface of joints was detected by ultrasonic inspection. Moreover, the surface area fraction of oxide film is in excellent agreement with the theoretical value calculated by shear strength. The result indicates that surface oxide film is the dominant barrier on the diffusion bonding of bulk metallic glass rather than low atomic diffusion coefficient.