Abstract: Non-isothermal crystallization kinetics behavior of fly ash (FA)/polypropylene (PP) composites was studied by differential scanning calorimetry (DSC), and crystallization kinetics of Jeziorny and Mo methods was discussed, at last, The activation energy was computed by Flynn-Wall-Ozawa equation. The results show that, after adding FA into PP, the crystallization onset temperature (To), crystallization peak temperature (Tp), Avrami exponent n, half-time of crystallization (t1/2) and cooling rate F(T) of the composites increased, and crystallization rate constant (Zc) decreased. When FA adding content was 15wt%, t1/2, activation energy and F(T) was the smallest, and Zc was the highest. The activation energy of the composites were higher than the pure PP.