Abstract: In Bohai Sea, one of the red-tide worst-hit areas of China, the red-tide disasters occurred frequently and aggravated in recent years.Effectively monitoring the processes of the red tide from happening to extinction is of great significance for Bohai Sea.Based on MODIS (moderate resolution imaging spectroradiometer) data, five methods including the chlorophyll concentration anomalies, the red tide index, the Rrs band ratio method, the red band difference, the Karenia brevis bloom index have been comparatively analyzed to examine their availability for red tide extraction in Bohai Sea.The results showed that these five methods could effectively extract the red tide information in the offshore area of Tianjin Binhai tourism area.Not only the range but also the spatial distribution of remote sensing detection agreed with the fact.In contrast, the red tide extraction by these five methods indicated a distinct difference in the offshore area of Qinhuangdao area, which was relatively reasonable for the chlorophyll concentration anomalies and the band ratio method.However, no matter what the method was used, the field survey data or ERGB (enhanced red-green-blue) composite was necessarily combined to validate the performance of red tide extraction at different times or in different regions.