By using Doppler weather radar data on 46 thunderstorms from 2002 to 2 007 in Tianjin and observing data of AWS, according to the echo characters on th e data, there are four kinds of echo characters, including bow echo, gust, strip echo and isolated echo. Especially, bow echo can cause great losses. Meanwhile, the sources of thunderstorm have the following four aspects, including north pa th, northwest path, west path and others. The situation mentioned above can be a pplied for warning of thunderstorm in Bohai bay and others area.