With the NCEP/NCAR reanalysis data, the background conditions, under which 33 cases of convective merger occurred in the Jianghuai region during the summers of 2005 and 2006, are analyzed. It is shown that these circulation patterns for merging can be classified into five types: merging before a trough in North China, behind a trough in North China, inside a subtropical high pressure, outside a subtropical high pressure, and inside an east wind system. The dynamic and thermodynamic conditions triggering the five kinds of convective merging are different. In addition, the impact of the mountainous terrain on ground temperature and energy is closely related to the occurrence and merging of convective clouds.