Abstract: In this paper, the damage index method is used to determine the number of defects. Aiming at the artificial nature of the defect value range in the damage index method, the reasonable value of the defect search range is deduced and the search range is further reduced. At the same time, an improved artificial bee colony algorithm considering nonlinear factors is proposed to accelerate the iteration processes of objective function minimization in the process of multiple flaw detection. Finally, three examples show that the proposed method has a good inversion effect for identifying both regular and irregular defects in structures.