Extensive patches of floating algae have appeared since mid-June in coastal waters off Qingdao, China (Hu and He, 2008). The objectives of this study were : (i) to monitor the movement of green algae patch using the Moderate Resolution Imaging Spectroradiometer (MODIS) time series in the East China Sea and Korean Seas, (ii) to analyze and compare the shapes and sizes of green algae patch by using multi-sensor satellites data such as MODIS, ALOS AVNIR-2, Landsat ETM+, Kompsat-2 MSC. Ocean color remote sensing data is efficient for short and fixed term monitoring because of highly temporal resolution. But relatively lower spatial resolution (1,000m <) of ocean color remote sensing data make it difficult to detect the detail shape of green algae. Therefore, we used the MODIS (250m; band 1 and 2), ETM+ (30m), AVNIR-2 (10m) and MSC (4m) data having more high spatial resolution. MODIS-250m normalized difference vegetation index (NDVI) processing is efficient for the detecting of shapes of large-scale green algae patch. Most of the green algae are distributed around the coastal area of Qingdao, and some of them were getting smaller and moved to the southern sea of Korea. MODIS couldn’t detect small size of the green algae distributed around the southern part of Korea because the size of patch is less than 500m height. As compared with the last year data, the green algae distribution highly increased during summer season in 2008. Multi-sensor integration study has the potential to provide synoptic information of coastal environments monitoring.