Red tides occurred frequently in the East China Sea in recent years. A red tide dominated by Prorocendrum donghaiense and Karenia mikimotoi happened in the Zhejiang Coastal Waters in late-May 2005. EOS MODIS water color data were utilized in extracting the red tide information. Sea surface temperature data derived from NOAA AVHRR and EOS MODIS were also analyzed to understand the possible formation mechanism of this red tide. The relationships between the red tide and related oceanographic features were discussed based on image data. The results indicate that the red tide was associated with several oceanographic processes, such as coastal front. This study showed that the combination of remote sensing data of water color and sea surface temperature can be useful in studying and understanding the oceanography of red tides.