In this paper, characteristies of frontal surface and vertical struetural types of temperature and salinity in the northwestern part(28°-32°N, west to 124°E) of the East China Sea are preliminarily analysed using data observed 1958-1965 and 1971-1974. It was found that there are two front surfaces, one on the eastern side and the other on the western side of the area. based on the characteristics of the curves of temperature and salinity versus latitudinal distance and on the principle to give more attention to salinity than temperature. The western front surface is located between 122°10′E and 122°40′E, and comparatively steady at all times of the year, with only a few periodical (semi-diurnal tidal cycle) perturbation owing to the tidal influences.Eastern front surface position and its salinity show clear seasonal variation on account of the influences of the Changjiang (Yangtze) runoff at the surface, and the clear effect of the Taiwan Warm Current on the deeper layer. The vertical structure of temperature are divided into five types in this region:vertical homogeneous type, positive gradient type, negative gradient type, intermediate warm water type and intermediate cold water type. While the vertical structure of salinity are divided into only two types: the vertical homogeneous type and the positive gradient type. The above-mentioned vertical structural types of temperature and salinity appear alternatively in a year. Vertical homogeneous type was almost distributed all over the area for half a year of cold weather. The negative gradient type temperature and the positive gradient type of salinity occured mainly in the warm weather for half a year.