Dafan Nuclear Power Plant in Tongshan, Hubei is the first one situated at the mainland permitted by the national government in China. In order to abso lutely ensure the safety of that plant, the evaluation of the basic climatic pro perties (including the properties of disasters) and designed parameters of the squall lines is very important in the preceding period. Based on the primary dat a collected from the area of 80 km×80 km around the nuclear power plant in Tong shan, Hubei from 1956 to 2000 through many ways such as the record in meteorolog ical stations, the collection of disaster events, and the report of climate impa ct assessment, the characteristics of temporal and spatial distributions and disa sters of the squall line events are analyzed and compared with that of tornado e vents. It is revealed: (1) There is apparent temporal (daily, monthly, seasonal, d ecadal) distribution for the squall line events that are mainly concentrated in summer and spring especially in July, August and April, from midday to early e vening especially at afternoon, in the 1980s, all these are similar to that of tornado events, but the average lasting time for all squall line events is abou t 95 min that is longer than the average lasting time (17 min) for all tornadoes. (2) There are very apparant local properties for all squall line events, such as Hua ngshi at northeastern part of the plant and Xiushui at southern part of the plan t with the most frequent events, and Tongshan and Chongyang at the central part of the plant with no events at all in the recent 31 years, which are determined by the local position, topography and the moving paths of synoptic systems. (3) The moving direction is mainly concentrated from NNW to SSW, especially from WNW to WSW. (4) Apart from storms when squall line events occur, there are strong li ghtning and heavy rain together that will make the disasters more serious. (5) Co mpared with tornados, there are a little bit smaller wind speeds for squall line events, thus a wind scale of 12 is closed as the designed speed.