Analysis of two series of nine each grab samples, obtained in various months from May,1983 to May, 1984 in stations 5206, and 5207, revealed the patterns of benthos quantity dynamics in an upwelling area in Taiwan Strait. The diversity index (H’) and evenness index (J’) of various benthos samples were all more than 3 and 0.7 respectively. Those indicate some of benthos community structure are similar to lower latitude waters. But there are two and five species being dominant respectively, Which show other community structure is similar to midle and higher latitude waters. On the other hand, the similarity index (S) of pairs of samples taken in warm season months were all more than 0.4 and this is also in the cold,but ones taken in warm and cold season months were lower than this, indicating the difference in community structure in warm and cold season.