Abstract: Nonisothermal crystallization behaviors of PE-HD/PE-UHMW blends were investigated by differential scanning calorimetry, their crystallization kinetics were analyzed by Jeziorny’s and Mo’s methods, and their crystallization activation energy was evaluated by Kissinger’s and Takhor’s methods. The results indicated that PE-UHMW could act as a nucleating agent to provide more activated nuclei for the crystallization of PE-HD and thus enhance its crystallinity through heterogeneous nucleation. As a result, the crystallization onset temperature, crystallization peak temperature and crystallization rate of PE-HD were improved. It was also found that the blend containing 10 wt % PE-UHMW achieved a minimum value in crystallization activation energy but a maximum value in crystallization rate.