There are very serious problems on installing the implant and on gaining osseointegration because atrophy of the edentulous ridge, pneumatization of the maxillary sinus and poor quality often limit the volumn of bone available for implant. Also, anatomical variations of maxillary sinues are a complex factor in deciding the treatment methods. When ridge is atrophic, many clinicians advocate augmentation of the maxillary sinus to increase the dimension of the available bone for implant placement. One of these is the "Sinus bone graft" procedure. In sinus bone graft, there are one-staged method where implant is installed immediately after sinus bone graft and two-staged method having osteogenetic period with delayed impants placement. Most of all, if the bone height is more than 4-5mm, we usually choose one-stage method and if it's less than 3mm, it's better to use two-staged method. But in the cases of using tapered porous surfaced implant, there are many benefits for early implant fixation with wedging effect. We performed the onestaged sinus graft using the tapered porous surfaced implant in below 3mm bony height of maxillary sinus. We present the case reports with the literature reviews.