Abstract: The ultrasonically aided brazing of 55vol% SiC_p/A356 composites in air using Zn-Al alloy as a filler material is investigated.The microstructure of brazed metal is analyzed with scanning electron microscopes and EDAX, the regular effect of ultrasonic acting time on microstructure and shear strength of brazed metal is studied, and the illustration of the formation of composite joint under the ultrasonic vibration is established.The average shear strength of the brazed bonds reaches 231 MPa when brazing at 475℃ with application of ultrasonic vibration for 20 s.The shear strength of the composite bonds increases by 50% than that of the brazed bond without SiC particles.The increased strength is associated with the increase of the aluminum content and the quantity of reinforcement particles in the bond metal.