This paper mainly researches on the contact-reaction brazing of AZ31 magnesium alloy and 6061 aluminium alloy by adding the Zn-7 Al metal middle layer,and analyzes the microstructure and mechanical properties of brazing joint by 3 D digital video microscope and hydraulic universal testing machine. The result shows the joint strength of the middle layer contact-reaction brazing of AZ31/Zn-7 Al/6061 is higher,than that of the direct contact-reaction brazing with Mg/Al. In the middle layer,Zn is a suitable matrix metal because Zn can react with Mg and Al to generate good properties phase which has a certain strengthened effect on the properties of the joint.