Abstract: In view of the problem in bonding oxygen-free copper strip flexible conductor, diffusion welding experiments for oxygen-free copper strips were carried out with silver coated oxygen-free copper and BAg45CuZn filler metal as interlayer and no interlayer at a temperature of 740-940 ℃ in the vacuum hot-pressing sinter．The welding joints were studied through test of tensile shear force, electrical conductivity and hardness, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). The results show that the tensile shear force of the joint without interlayer was increased with the increase of the diffusion welding temperature and holding time. When diffusion welding temperature rose, surface hardness of the joint without interlayer decreased, but conductivity increased slightly. The strongest tensile shear force was given by the joint of oxygen-free copper strip with filler metal as interlayer, and its bonding interface belonged to brazed connection.