Abstract: Based on the study of biological oceanographic characteristics of planktonic copepods in the waters north of Taiwan Province a Ⅱ-community characters,the relationshipe between various eootype indlcators and different water masses are discussed.The results show as follows:the abundance distributions of Undinula vulgaris and Eucalanus pileatus can indicate the seasonal ehanges and extending trends of the Taiwan Strait water.Euchaeta marina can refeet the influencing degree of the Kuroshio surface water.The distributions of tropic oceanic lower-temperature and high-saline species in the shelf area can indicate the scope of invading and upwelling of the Kuroshio subsurface water.The distributions of Calanus sinicus can reflect the seasonal difference of the coastal water expanding.Probably affected by transverse circulation in the shelf,Calaanus sinicus can extend to outshore area.Under this circumstance,the adaptability of the species for lower temperature causes its abundance to be higher in waters with relative low temperature.By researching the distributions of species of tropic oceanic Iow-temperature and high-saline group,it is found that the widespread distribution of Calannides carinatus in the shelf area in spring is probably because of the fact that the species occurs in the upwelling in Minnan-Taiwan Bank Fishing Ground waters in winter and then is carried forwards to north area with the Taiwan Strait water in spring.However,the occurrences of Calanoides carinatus and other two species of this group in the Iow layer of the slope show that the middle and deep waters possibly spring in the waters southeast of the survey area.