Accelerated aging test for acrylonitrile-butadiene rubber was carried out with two compression ratios at four different temperatures in 10^# hydraulic oil. The molecular structure,Tg and thermal properties of nitrile butadiene rubber before and after storage were characterized by FTIR,DSC and TGA. The results showed that the reliability of the shelf-life deduced by accelerated aging test was high. The aging of acrylonitrile-butadiene rubber after 12 years was not obvious.