The Bonebridge is an active bone conduction implant (BCI) that is primarily indicated in patients with conductive and combined hearing loss. However, many of these patients present with a radical cavity as a result of previous surgery. And the site of implantation would be determined with only simulation on CT. To ensure the best possible acoustic transduction, the Bone Conduction-Floating Mass Transducer (BC-FMT) should be positioned near to the cochlea. This requires precise identification of the sigmoid sinus, which cannot be achieved accurately enough using external anatomical landmarks. We thus report on a patientin whom the Bonebridge was implanted using CT-guided navigation. We compared the markers of implantation on CT images before the surgery with the markers of 3D-navigation images during the surgery. We got the good coinsistence between those images and good performance of bonebridge for hearing. So We report this case for using exact measurement of the site of implantation with Bonebridge.