In order to investigate the vibrational characteristics of wall type improved ground by Deep Mixing Method and to evaluate the present earthquake-resistant design method for these kind of the improved ground, the vibration tests on model in the shaking table were carried out. In tests, two sizes of the wall type improved ground were used. Dimensions of one of them are 1.0m in height and 2.59m in length and others are 1.0m in height and 2.13m in length. Improvement ratio is about 56%. Improved ground is on the sand layer. Main results are summarized as follows: 1) The dynamic behaviors of the improved-soil wall are identical to those of the unimproved soil between the treated-soil walls. 2) The wall type improved ground behaves like a rigid body. 3) The imprved ground slides in the direction of sea side under strong motion. 4) Accelration of the wall type improved ground equals to those of the sand layer under the improved ground before the improved ground slides. 5) As the table acceleration increases, dynamic earth pressure of clay acting on reclamation side of the improved ground increases and that acting on sea side the improved ground decreases. 6) It was found that the present earthquake-resistant degisn method is able to evaluate the stability of the improve ground.