In this paper, the pull-out characteristics of composite Z-pins with various groove shapes was investigated. The groove shape of composite Z-pins was made by applying temperature and pressure to the top and bottom of laminated composites inside the autoclave. Then, the dumbbell type of pull-out test specimen was made by applying adhesive bond. Six types of pull-out test specimens were fabricated by changing the groove length. Pull-out load and displacement sere observed for those specimens with different groove ratio. The results show that the maximum pull-out load of the grooved pin with grooved ratio 0.4 was increased up to 30.6% by comparing the plain pin. The grooved pin has a high pull-out resistance even after the fracture of the interface.