In summer, the deep convection motion over Tibetan plateau and its adjacent regions is most active. One deep convective system occurred over the southern slope of Tibetan plateau on July 12, 2009 is analyzed by using the data from two infrared channels of FY-2C meteorological satellite and the reanalysis data from ERA-Interim. The results show that because of the synthetic action of topographic lift and cyclonic pumping in upper atmosphere, the convective system over the southern slope of Tibetan plateau has a higher deep convection development altitude. At this time, if the water vapour in the lower part of the troposphere is transported upward to the top part of the troposphere, it would benefit the exchange of substance between the stratosphere and the troposphere. Both the position of a convective system over plateau and its adjacent regions and the distribution of temperature gradient and vapour gradient in lower part of troposphere have significant influences on the development of convective systems.