The extremely heavy rainfall, persistent rainfall and severe convective weather events occurred frequently over SichuanChongqing Area and YangtzeHuaihe Riv er Basin during the summer of 2007. Based on the FY2C TBB (equivalent temperat ure of black body) dataset during 28 June-26 July 2007, the 570 MCSs (mesoscale convective systems) with life-cycle greater than 3 hours were investigated over the former two areas and adjacent areas (25°～38°N,100°～130°E). There were four activeMCS areas: the area from the western Sichuan Province to nort hwestern Yunnan Province, the eastern Sichuan Province and Chongqing City, the e astern YunnanGuizhou Plateau and the area from northern Guangxi Zhuang Autonom ous Region to Dongting Lake and the YangtzeHuaihe River Basin（YHRB）, and the re were three minor activeMCS areas over the YHRB activeMCS area. The modal duration of the total MCSs and those over SichuanChongqing Area were approxima tely 3～5 hours, but the modal duration of the MCSs over YangtzeHuaihe River B a sin was about 5～8 hours. The MCSs were classified as three types by the time sc a le of MCS: the first type of MCS has a life cycle of 3～5 hours， the life cycle of the second MCS type is 6～11 hours and the life cycle of the third MCS type ≥12 hours. The trigger mechanisms of the three MCS types were different: the fi r st and second MCS type could occur inside and outside the mean location of the W est Pacific subtropical high, and their occurrence, development and movement wer e obviously influenced by the mesoscale weather systems and may be related to th e factors such as topography and mesoscale convergence lines; the third MCS type occurred outside the mean location of the West Pacific subtropical high, and it s occurrence, development and movement were obviously influenced by the larges cale synoptic systems. The diurnal variations of the three MCS types were also o bviously different. The peaks of the three MCS types all occurred in the afterno on. However, the first MCS type had no obviously nocturnal occurrence, but the s econd and third MCS type had a nocturnal occurrence characteristic. The most act ive peak of the first and second MCS type was both in the afternoon, but the mos t active peak of the third MCS type was after midnight (about 18UTC). Both the M CSs over SichuanChongqing Area and YangtzeHuaihe River Basin had multiple ac tive periods in a whole day, but the active periods of the MCSs over two areas w ere different. Finally, two typical MCSs causing heavy rainfall and one longdu ration MCS were presented.