Based on meteorological observational data and FY2C TBB，a typical mes oscale con vective complex in South China on May 6, 2006 was analyzed. It shows that the su rface cold air movement and the couple of high and low level jets are the keys t o the formation and development of MCC under the unstable and plentiful vapor co nditions. The trumpetshape landform and the temperature change of underlay als o contribute to its evolution. A squall line in MCC was monitored by using termi nal Doppler radar and AWOS, and the value of lowlevel wind shear was calculate d to provide for Guangzhou Baiyun airport.