Abstract: Integrating research on phytoplankton of the Taiwan Strait by scholars from the Chinese mainland and Taiwan, we proposed a list of 620 phytoplankton species. We also identified their ecological groups and distinguished red tide species. Furthermore, based on 344 samples collected from the Taiwan Strait in four seasons from May 1984 to February 1985, we analyzed the distribution pattern of species and the spa-tio-temporal variation of species abundance. Of the 299 species identified in this survey, 199 species be-longed to Bacillariophyta, whose abundance accounted for 99.25% of the total. The maximum species num-ber and abundance of phytoplankton both occurred in August, while the minimum appeared in February. Compared with coastal waters, strait waters had more phytoplankton species but lower abundance. The rela-tionships between the distribution of phytoplankton and environmental factors are also discussed.