The electrical conductivity of the cement based  materials mainly depends on the properties of its pore solution, and its freeze-thaw cycling damage properties are related to the pore size and distribution definitely. This paper has studied on the relationship between the electrical resistivity variation and the freeze-thaw cycling damage behavior of the autoclaved fly ash brick. Test results show that, the hysteresis effect of the electrical conductivity of the autoclaved fly ash brick has been changed significantly, whereas its frost-resistance ability decrease in quantity with increasing amount of fly ash added. Bricks with more cement added give high frost-resistance ability, such that the remarkable descent stage of them change from -10~0 ⁰C to -20~0 ⁰C. The addition of air entraining agent has little or undesirable effect on the frost-resistance ability of the autoclaved fly ash bricks.