This study introduces a result of sea-ice detection using SAR and GOCI about a difference between sea water and ice which show different characteristics due to reflexive properties of matter. SAR is advantageous to detect in cloudy weather, but GOCI cannot observe sea state through cloud area. In order to getting more accurate water-ice boundary with combination of both SAR and GOCI images, this paper especially compared both images in Bohai Bay, China in the two winter periods from December to February, 2010-11 and 2011-12. As a result of the analysis, it acquired the beginning point and the first day of freezing sea water, the extent of iced area, and speeds of freezing. Also, this monitoring can identify the day of forming maximum iced area and the day of melting sea ice....her, but GOCI cannot observe sea state through cloud area. In order to getting more accurate water-ice boundary with combination of both SAR and GOCI images, this paper especially compared both images in Bohai Bay, China in the two winter periods from December to February, 2010-11 and 2011-12. As a result of the analysis, it acquired the beginning point and the first day of freezing sea water, the extent of iced area, and speeds of freezing. Also, this monitoring can identify the day of forming maximum iced area and the day of melting sea ice....