The thermal stabilization of PI / Al2O3 hybrid films was studied with TG. Meanwhile, the kinetics parameters (activation energy of thermal decomposition, collision coefficient and action progression) were calculated, and the upper limit temperature was predicted according to the relevant data. The experiment results showed that the order of reaction in air atmosphere was bigger than that in nitrogen atmosphere, and tended to second-order reaction. The value of E calculated by the method of Kissinger was lower than that in the method of Coats-Red fern. The collide coefficient (A) was calculated in the method of Coats-Red fern selected by contrast, and the upper limit temperatures of hybrid PI material was nearly 300 ℃ similar to those reported in previous literatures. The results have shown that Coats-Red fern method is one of the reliable methods to predict the long-term life upper limit temperature of hybrid PI materials.