Abstract: In this paper, a procession of squall line in warm sector of Jiang-Huai area in April 27,1983 is analysed,which is based on the conventional data,densed data of mesoscale weather experiment of East China, temperature,pressure,humidity, wind and recording precipitation, satellite and radar data of surface. Some character of squall line which goes by DanBei Mountain propagates from west to east. When it reaches the axis of jet of south-west of low level, the convective tensity varies. The phenomena of heating of short time and shower occurs when the squall line passes. The surface pressure of squall line consists of mesoscale low in front of squall line, mesoscale high and mesoscale low behind the squall line. A warm and moist inflow is in front the squall line. This inflow comes from low level of atmosphere. There is a downdraught which comes from high level behind the squall line. The field of pressure, temperature and wind and synoptic type of this squall line are different from classical squall line and from midlatitude squall line of U. S. A. and tropical zone's.