In this paper, the results of lateral loading tests on two types of CLT shear wall systems with an opening are summarized, one is the shear wall system with assembling narrow size CLT panels and another is that using one large size panel with an opening. 8 types, 13 specimens in all were tested. Load-displacement curves were obtained and characteristic values of shear performance were derived. As a result, the assembly system revealed higher ductility because of the ductility of connections between panels, while the rapture of large panel system was brittle though the shear capacity was higher than the assembly system.