Marine oil spills, caused by offshore oil and gas production, ship collisions, and natural seabed seepage, refer to the pollution phenomenon of crude oil leaking onto the ocean surface. Oil spills not only lead to economic losses but also severely pollute the marine environment and damage ecosystems. Therefore, monitoring marine oil spills is essential. Synthetic Aperture Radar (SAR) technology has become a vital tool in oil spill detection due to its all-weather, day-and-night observation capabilities, providing unique advantages for marine oil spill monitoring. With advancements in SAR technology, acquired images now enable continuous monitoring of the same sea area, allowing researchers to study oil spill distribution patterns. The Bohai Sea, a region with intensive human activities, heavy ship traffic, and offshore oil and gas operations, is highly prone to oil spills. The primary objective of this study is to investigate the occurrence patterns of oil spills in the Bohai Sea through remote sensing detection. This study utilizes Sentinel-1 SAR data to conduct multi-year oil spill monitoring in the Bohai Sea. Based on the detection results, an oil spill intensity index is established, and annual oil spill intensity distribution maps are generated. The mapping results are then analyzed to assess interannual variations in oil spill intensity across the Bohai Sea region.