The goal of our study is to develop a data fusion system, which enables surgeons to easily visualize the inner structures of elastic organs during open surgery. We chose the liver as the focus of this study due to its easily deformable nature and complex vascular structures. To do so, we propose using preoperative data and supplementary intraoperative data We captured a sequence of liver surface data for the intraoperative data by using trinocular stereo and we applied them to the preoperative 3D model's surface. Then, we modified the model to fit the intraoperative liver condition and portrayed the model's inner structures. With this method, we could establish this system.