3,3′-Dicyano-4,4′-azofuroxan was synthesized from malononitrile via nitrosation,oximation,oxidization cyclization and azo-coupling. The yields of the above four steps could be 79.0%,86.8%,61.0% and 71.9% respectively,and its overall yield was up to 30.2% The mechanism of oxidization cyclization was proposed and discussed,and the key factors,including the molar ratio (n) of lead dioxide/1-amino-2-nitrildioxime and reaction time (t),of this process were studied. When n=4/1 and t=4 h,the highest yield of 4-amino-3-nitrilfuroxan could be obtained. The structures of the aim compound and all of the intermediates were confirmed by spectroscopical and elemental analysis.