Research on fly ash resistivity at low temperature has been studied a lot, but there are few experimental researches on fly ash resistivity at the temperature above 673 K. Eight samples were selected to be investigated. By DR2-1000 dust resistivity tester, experimental resistivity data of the fly ashes at high temperature were achieved. The experimental results at temperature of 673-1273 K were discussed. With the increase of temperature, the decrease of resistivity agreed with Arrhenius equation well. The existence of alkali metal and iron ions reduced the resistivity obviously. Size distribution showed influence on the electrical resistivity. But with the increase of temperature, chemical constitution played greater role in electrical characteristics. Most of the experimental fly ashes had resistivity value above 105 X cm at the temperature of 673-1273 K. (C) 2013 Elsevier Ltd. All rights reserved.