Abstract: The polychromatic spectrum leads to cup or streak beam hardening artifacts and reduces the image quality in X-CT(X-ray computed tomography).A new correction method for this problem is studied in this paper.As to the characteristic of noise in the high frequency mostly,we divide the projection into high and low frequency.And moreover,we adopt the improved method this paper researched to the low frequency,which is based on the physical property.Then,the result is added to the high frequency.At last,we verify it through experimental system and the result indicates the method can improve the image quality effectively.