Abstract: In order to investigate the thermal and mechanical properties of the wood powder/high-density polyethylene (HDPE) composites that filled with different kinds of inorganic nanoparticles (calcium carbonate NPCC, montmorillonite NMMT and alumina NAL), the thermal properties of the composites were analyzed by simultaneous thermal analyzer and expansion coefficient meter, the mechanical properties of the composites were also tested and analyzed. The results showed that all the three kinds of inorganic nanoparticles had a significant effect on the performance of wood flour/HDPE composites. Among them, NPCC could greatly lower the linear thermal expansion coefficient of wood-plastic materials by 38.95%. The composite material also has better thermal stability that the initial pyrolysis temperature increased by 2.8℃ during the heating process，and the carbon residue rate increased by 39.1% at 600℃.The tensile strength, flexural strength and impact toughness of NPCC modified wood fiber/HDPE composites also had great improvement (the increases were 32.86%, 11.05%, 35.30%, respectively).

Key words: molding, inorganic nanoparticles, thermal stability, mechanical properties