Abstract: The paper is the succession of the study on abundance distribution of planktonic copepods in the waters north of Taiwan Island, and the constructions and features of copepod community and the relationships with water environment are analyzed and discussed. The results show that totals of 237 species are identified and the construction of community is complex. The percentage of annual present species is only 32%.The mean values of diversity and evenness of the copepod community are 3.714 and 0.690 respectively, and their horizontal distribution patterns are higher in outshore area than in nearshore area. The copepods of the area can be divided into five ecotypes. The warm-water outshore high-temperature and lower-saline group and tropic oceanic high-temperature and high-saline group can indicate the seasonal changes of the Taiwan Strait water and the Kuroshio surface water respectively. According to the various aspects of calculation and analysis, winter is different from other three seasons in environmental conditions. In spring, summer and autumn, Undinula tralgaris is the most dominant species and salinity is the main factor that affects the community feature values. The communities in the three seasons have the subtropic-tropic characteristics in which warm-water outshore species are dominant and tropic oceanic species occupy also certain proportion. And in winter, the dominant species is Euchaeta marina and the temperature is the trtain factor influencing the community feature values. The community has the tropic oceanic chuacteristics in which tropic oceanic species are dominant.