In this paper, the vertical distribution patterns and fine structures of temperature and salinity in the middle and northern Taiwan Strait is studied based on data obtained with Nansen bottle and CTD system in two special cruises for"upwelling in July and August, 1987. The results show that the vertical distribution patterns of temperature and salinity are simple in this area in summer. For temperature, negative gradient is main in the area; the vertical homogeneous type and intermediate warm water type can only be found at a few stations. For salinity, only two types of vertical distributions, the homogeneous type and the positive gradient type, are found,and the positive gradient type covers almost the whole studied area in July and the vertical homogeneous type is dominant in August. Multi-ladder structure and fine structure phenomena also exist in the vertical distribution of temperature and salinity in the region, and the fine structure of temperature is more developed than that of salinity. For temperature, the appearance frequency of negative gradient layer is very higher than that of positive gradient layer. For salinity, the appearance frequency of negative gradient layer is lower than that of positive gradient layer. Their gradient values,however, are all small, commonly 0.05-0 10℃/m for temperature and 0.05-0.10/m for salinity. Their appearance frequency lowers rapidly with the increase of the gradient value. The thickness of positive (or negative)gradient layer of temperature and salinity is small in summer. Almost 75% of the gradient layers are 0.1-0.6 m thick.