By analyzing the NCEP 1°×1° 6 h reanalysis data and conventional and nonconventional observation data from May to September during 2007-2013, the warmsector rainstorms over the middlelower reaches of the Yangtze River are studied. The warmsector rainstorms in this area can be divided into three types based on the weather situation, which are coldfront, warm shearline and the edge of subtropical high. The statistical results show that the warmsector rainstorms occur generally in the warm sector being 100-300 km away from the shear line at 850 hPa (cold front on the ground). The significant characteristics obtained from the research are: (1) the coldfronttype precipitation often occurs in May and June, with weak intensity and uniform distribution. The warm shearlinetype rainfall usually occurs in the south part of this area with high frequency and strong intensity, mainly in June and July. The precipitation on the edge of subtropical high occurs least but with the strongest intensity and often in July and August. The orographic action of the Dabie Mountain and Wannan Mountain provide favorable conditions for local heavy rains. (2) Shorttime heavy rainfalls make great contribution to the rainstorm. (3) The warmsector rainstorms under the background of cold front generally happen in the prefrontal trough, and the rainfall area is closely related to the coupling of upper and lowlevel jets. In the second type, the rainstorms have high correlations with the structure of mesoscale jet and topographic forcing under the background of warm shear line in the lower level and stationary front on the ground. And the heavy rainfall happens on the edge of the subtropical high has close relations with accumulation of water vapor and the development of convective instability condition. Thus, three kinds of conceptual model have been built based on the above.