Abstract: In this paper, three-dimensional environmental meteorological fields for the life processes of eighteen mesoscale- convective cloud clusters over subtropical humid region of China during July—August of 1984—1985 have been analysed. Largescale meteorological conditions and three-dimensional structures associated with ten meso- convective cloud clusters over western China are mainly studied. It is shown that they are characterized as subtropical monsoon cloud clusters. The evolutions of convective clusters through east slope of Tibetan Plateau and their environmental conditions of continuative development in the moving eastforward are discussed.