Abstract:Based on the conventional observational data and NCEP 1°×1° reanalysis data, the rainfall distribution of zonal shear line heavy rain was refinedly analyzed. The results show that, although the location of low level shear line is important to the distribution of heavy rain, it is not the unique decisive factor to the distribution. The spatial structure of affecting system and the interaction between cold and warm air are essential to the heavy rain fine forecast. With the cold air invasion from the northeast region of China and northeast wind crossing Shandong Province, there are two rainfall areas. One is related with the shear line, and the other is caused by frontal uplift of the ground northeast of the heavy rain area. When a warm low is located in the northeast region of China and 850 hPa cold center entrenched in Shandong Province and there is a strong southwest warm air flow with shear line, the rainfall area of heavy rain is located between the shear line and the stationary front in South Shandong Province. Wind convergence center is often accompanied with high humidity area, and the rainfall area is usually located in the front of high humidity area and near wind convergence center.