Total 93 red tides events were recorded from 1981 to 2002 in Shenzhen coastal waters. During the 22 years, there are four featwres of the red tides:1)The red tide events were caused more in Dapeng Bay, Daya Bay and Shenzhen Bay. 2)The frequency of red tide events increased, and the duration of them extended. 3)There were two seasons during which the red tide events take place more frequently the on was from March to May, another was from September to November. 4)The diversity of red tide causative species increased, about 36 species were recored. 5)It seemed that there抯 an obvious trend on the succession of red tide causative organisms, and there were frequently new species causing red tide events.