Based on the information entropy theory, combined with the advantage of modal curvature index in the damage identification of beam structures, the modal curvature utility information entropy index is proposed. The index comprehensively reflects the damage state of the structure by calculating Mutual re-transformation matrix and the weight-probability coefficient. A simply-supported beam example is established to verify the index. The results show that the modal curvature utility information entropy index take advantage of the merits of the modal curvature index which is sensitive to damage and can overcome its shortcomings effectively. The index proposed can identify the damage location and damage degree accurately of structure and has certain noise immunity, which provides an effective damage identification method for beam structures. Finally, an actual simply-supported beam is taken as the experimental object to verify the effectiveness of the index in practical engineering. © 2020, Editorial Office of Journal of Vibration and Shock. All right reserved.