A total of 149 genus and 238 species of Radiolaria in cores from four stations in the Okinawa Trough are examined in this paper. Water depths and cores lengths at these stations are 602-1900 m and 1.7-2.4 m respectively (see Fig. 1). Based on the distributional characteristic of Radiolaria and the radio-larian temperature number (Tr), the climatic fluctuations since the last 150 000 years and the stratigra-phic classification are also discussed.