Abstract: Effects of Al on the spreadability of Zn-Al filler metal were investigated,moreover,the strength and microstructure of the brazed joint had been studied by brazing Al-Al and brazing Cu-Al.The results indicated that when Al content was 15%,the filler metal got the best spreadability on aluminum substrate.However,the spreadability decreases when Al content exceeded 15%.It was also found that the spreadability on copper substrate increased with the increase of Al content when Al content was changing from 2% to 25%.The spreadability on copper substrate was much lower than that on aluminum substrate.Furthermore,the mechanical property tests indicated that the strength of the butt joint of Al-Al and the joint of Cu-Al including the lap joint and the butt joint enhanced with the increase of Al content.The highest strength of the brazed joint was obtained when Al content was 15%.However,when Al content exceeded 15%,the strength of the brazed joint decreaseed.