In order to evaluate the shelf life of grease for bearing on aerospace craft and determine whether the material still can meet the requirement of use after longterm storage,hotair accelerated aging tests for a organosilicon grease were carried at four different temperatures to investigate its mass change fraction under different aging temperatures and times.The aging kinetic model and Arrhenius equation were used to fit the aging data,and the relationship between mass change fraction and aging time was obtained at different temperatures.The shelf life of the organosilicon at 25 ℃ was extrapolated by taking the mass change fraction of the grease as the extrapolation index.Results show that the shelf life of the organosilicon grease is more than 17 years at 25 ℃ when the mass change fraction of the grease is 0.076，and the main properties of the material still meet the requirement of use.