Al/SiC composites were prepared by sintering aluminum powder and silicon carbide particles. The diffusion welding was conducted on the composite with fillers of Al-20SiC (mass fraction/%), Al-20SiC-20Zn, and Al-20SiC-40Zn as interlayer materials at 420,520,600℃, and the effects of Zn content in filler and welding temperature on the properties of joint of the composite were studied. The results show that the Zn near the joint was obviously agglomerated after welding at 420℃, and was not agglomerated after welding at 520, 600℃, indicating relatively high welding temperature contributed to uniform diffusion of Zn. The oxidation occurred at the joint after welding at 520℃ with Al-20SiC-40Zn filler, resulting in the obvious cracks at joint. The shear strength of the samples after welding with Al-20SiC-20Zn filler was bigger than that with Al-20SiC and Al-20SiC-40Zn fillers, and increased with increasing welding temperature. With increasing Zn content in the filler, the hardness of the joint increased, and was higher than that of the base metal. The hardness of the joint increased with increasing welding temperature, but the increase amplitude decreased.