The present application relates to a cone beam computed tomography image correction method and system. The method comprises: acquiring a background projection image and a corrected die projection image under a first condition, according to the background projection image and the corrected mode projection image, the multi-energy curve being acquired, the single-energy curve being acquired accordingto the multi-energy curve, according to the multi-energy curve and the single-energy curve, the projection image to be corrected under the second condition being corrected and the target cone beam computed tomography image being generated. The method can obtain multi-energy curves and mono-energy curves with higher accuracy through the second condition, and accurately correct the projection imageof the object to be measured, so as to improve the accuracy of hardening correction.