It is impossible to study the relationship between water damage and voidage of asphalt pavement because the voidage of pavement core sample cannot be determined accurately. Based on the industrial computed tomography (CT) scanning technology for core samples of real void fraction measurement, dynamic water flushing apparatus to water damage damage of core samples, the CT scan void fraction and destruction after the relationship between splitting strength and CPN rutting depth of core samples, respectively, set up different lanes of void fraction and cleavage strength and the fitting formula of rut depth.