Abstract: In X-ray TICT, the variation of attenuation coefficient with energy leads to low energy radiation being absorbed preferentially. In orther words ,it is the more high energy, the more low attenuation coefficient. With the transmission thickness augmenting, it is easier to transmit the matter for X-ray. The phenomenon is energy spectrum hardening. Thus, hadening correction has to be done. In this paper, not only is energy spectrum hardening analyzed by theory, but also the numerical analysis of precise accurate theory model for hardening correction of energy spectrum and theory method which has been presented in the literature and that observes to the law of Beer and the characteristics of X-ray internal material are reasoned out for X-ray TICT, which also is with reference to Simpson formula. Then, the attenuation coefficient that has been corrected is used for product back-projection reconstruction.Thus, the effect caused by X-ray beam hardening is wipped of effectively for X-ray TICT.