Abstract: The room temperature density, thermal diffusivity and specific heat of 55CrMo steel had been measured by displacement way, flash method and comparison method, respectively. And the heat conductivity of the steel was also be calculated. The results show that the specific heat of 55CrMo steel increased generally with the increase of temperature, while the thermal diffusivity and heat conductivity changed in a contradictory tendency. All these these parameters fluctuated during the temperature zone of phase transformation. The experimental results provided some important data for the numerical simulation of induction quenching process of 55CrMo steel.