Abstract: Two disastrous weather events in July 2004,the local heavy precipitation caused the serious traffic jam in Beijing July 10 and a squall line associated with the severe convection caused seven lives loss in Shanghai July 12,turned into the focus of the public and government authority attention.The primary research of observational analysis and theoretical estimation suggested that both of them were caused by meso-β-scale convective systems (MCS).But,the infrared satellite images of GOES shown that the MCS caused heavy precipitation of Beijing had irregular external form,higher temperature of cloud top,un-smooth edge of cloud body,and weak temperature gradient.Those characteristics were different to the normal MCS.Otherwise,both two cases toke place when the large-scale circulation were in verystrong meridional situation and the Asia summer monsoon pushing northward exceedingly too,but the locations of two MCSs occurrence were different considerable.Finally,the scientific problems were suggested which are the internal structure and development conditions of this kind of at ypical MCS,and the relationship between the exceedingly pushing northward of Asia summer monsoon and the global general circulation.