Due to all kinds of correction algorithms have little effects on streak artifact at present,the reason of streak artifact is analyzed.Therefore,considering that the influence of soft tissue caused by the X-rays which penetrate through different bone thicknesses are different,the soft tissue correction polynomial in Bi-Polynomial correction method is improved based on H-L consistency condition.Forbild head phantom simulation results show that the improved algorithm can get better correction effect on both cupping artifact and streak artifact.