Abstract: Through 43℃ accelerated oxidation storage method, this paper studies the change law of FCC gasoline in stability with characteristic indexes of the colloid free of washing, actual colloid, acidity, color and induction period, and analyzes the influencing factors of the stability of FCC gasoline with mathematical methods, such as least square method, correlation analysis, variance analysis, and establishes the relation model between stability index and storage time as well as quantitative relations among stability indexes.The results show that during the storage process of FCC gasoline, the oxidation reaction of unsaturated hydrocarbon can cause quality decay, the stability will become worse with passing of storage time, the different raw materials can cause the different quality decay rate of FCC gasoline, and in which, the impacts of stability is greater than that of storage time; the colloid free of washing and acidity have close relation with actual colliod, with a correlation coefficient over 0.9, and it has closed relationship between the decay rate of the two kinds of colloids and chemical components, suth as cyclohexyl-containing organosilicon, diolefin, etc.