Abstract: Abstract The effects of alumina(Al2O3) on the crystallization and thermal conductivity properties of Polyethylene (PE) were studied in this paper. The experimental results show that the addition of Al2O3 has no effect on the crystallization behavior of PE. With the increase of Al2O3 content, the thermal conductivity and diffusivity of PE/Al2O3 blend increase. Due to the high crystallinity of HDPE and the easiness of forming the thermal conductive channels, the thermal conductivity and diffusivity of HDPE/Al2O3 blend are higher that those of LDPE/Al2O3 blend at the same Al2O3 content. In addition, the thermal conductivity measured through experiments corresponds with the data calculated with Agari model.