To solve the problems of high temperature, long holding time, vacuum environment and active elements when vacuum brazing porous ceramics, this work used ultrasonic assistance to realize the rapid wetting of porous ceramics, and the effect of ultrasonic power on the wetting effect was studied. The results showed that the Sn9Zn nonactive solder wetted the porous ceramics within 10 s at 230 ℃ under ultrasonication. When the ultrasonic power was 333.3 W, the solder infiltrated the ceramic matrix by a width of 25 μm. The width of the infiltration layer increased with increasing the ultrasonic power. The width of the infiltration layer was 80 μm when the ultrasonic power was 1000 W. Due to the low temperature during the wetting process, the residual stress in the infiltration layer after cooling was low, and thus the ceramic and the solder were closely bonded without cracks. The results of transmission electron microscopy showed that the wetting interface was enriched with oxygen and zinc elements. In this work, the rapid wetting of the porous ceramics can be attributed to the intense cavitation of the solder inside the microchannel of the porous ceramics. The extremely high temperature and pressure caused by the collapse of cavitation bubbles caused the non-active solder to rapidly wet the porous ceramics.