Abstract:The remote sensing result of blue algal bloom in Lake Tai from 2003 to 2007 shows that in resent years the blue algal bloom in Lake Tai has the follow ing characters: (1) The frequency and area of the bloom trend increasing; (2) Th e break out seasons of the bloom is tending to winter and spring; (3) The highes t frequency and the most serious areas of bloom appear mostly to be in the west and north of the Lake. Beside the contamination, meteorological characters can a lso impact on the break out of blue algal bloom. Through the analysis between field measurement and remote sensing data, it was found that the temperature, wind, li ght and precipitation can all impact on the bloom. In the above four factors, temperature and light ha ve a po sitive effect while wind and precipitation have a negative effect. It was also n oticed that because of the changing of pollution’s state, the degrees of effect are also changing.