The spatial structure characteristics of Zhejiang and Fujian (Zhe-Min) coastal water (ZMCW) were analyzed in this study, using achieved ocean data collected in the offshore area of Zhe-Min during winter 2006. The evolution of the ZMCW was then explored using the CTD data in the Taiwan Strait during winter 2001, spring 2002 and autumn 2002, combined with the salinity data from ocean stations at Sansha, Beijiao, Pingtan, Chongwu, and Nan’ao, all located along the coasts of Fujian and Guangdong. The results indicated that the ZMCW exists in the Zhe-Min coastal area, and its eastern boundary is roughly parallel to the Zhe-Min coastline. The average distance between the eastern boundary of the ZMCW and the Zhe-Min coastline is about 55.8 km, with the maximum being about 94.5 km. The influence depth of the ZMCW increases southward gradually from south of Qiantang Estuary in Zhejiang, which reaches its maximum (42.0 m) in the offshore region of Minjiang Estuary in Fujian, and then decreases gradually southward from there. The ZMCW appears and extends to Sansha and Beijiao first in September, but does not reach Pingtan. In October, it moves further southward to Chongwu. The ZMCW peaks during November and the following February when its southern boundary reaches as far as the adjacent area between Dongshan Island of Fujian and Nan’ao Island of Guangdong. It begins to weaken in March or April. In May, it retreats to the adjacent area of Pingtan Island, and almost disappears in June.