Abstract: The wettability of various aluminum base filler metals on SiC, 6061and SiC_p/6061composites is investigated. The results show that in furnace brazing,the compositions of filler metal and flux,the heating temperature and holding time, matching of melting temperature of filler metal and flux will influence the wettability of aluminum base filler metals, and in vacuum brazing, Al-28Cu-5Si filler metals containing magnesium behave non-wettable to SiC substrates in the temperature range in which the composites can be brazed, while matched with QJ201 flux, Al 28Cu-5Si-2Mg filler metal becomes wettable to 15% SiC_p/6061composites, but under wettable to 30% SiC_p/6061composites. On the contrary, Mg in the aluminum base filler metals will be detrimental to wettability on aluminum alloys and aluminum matrix composite when flux is adopted. It is found that the segregation of SiC particulates appears on the brazing interface of Al-28Cu-5Si-2Mg filler metal and 15% SiC_p/6061composites.