Abstract: Non-isothermal crystallization behavior of linear low density polyethylene (PE-LLD)/nano-Al2O3 composites was investigated using differential scanning calorimetry. The non-isothermal crystallization kinetics was analyzed with Avrami and Mo methods. Kissinger method was used to estimate the activation energy for non-isothermal crystallization. When the content of nano-Al2O3 was between 5 % and 10 %, the heterogeneous nucleation in the crystallization process of PE-LLD was sufficient, the crystallization onset temperature, peak temperature, and crystallization rate increased only slightly. The addition of nano-Al2O3 decreased the activation energy of PE-LLD.