In this paper, the delamination behavior of curved laminated composites with initial defect was studied numerically by using cohesive zone modeling (CZM). Cohesive elements were inserted between the ply interfaces to represent the occurrence of delamination. The finite element model was first verified by comparing the results with those of the literature. Next, the finite element analyses were performed for models with initial defect of pre-delamination and voids. In the results, various delamination initiation and propagation behavior were investigated. The effect of varying presence and location of pre-delamination and voids were systematically examined.