Abstract: The conventional and satellite data were collected and sorted by the Research Project Group of Cause and Prediction Application of 1998 Yangtze River and Nunjian River heavy rain. Besides convent ional physical variables such as vorticity, divergence, vertical velocity θse to represent the basic characteristics of atmospheric motion, We calculated thermodynamic parameter CD which reflects the sloppy development of vert ical vort icity and the diagnostic variable U which reflects the unbalanced quality of mesoscale atmospheric motion and variability of vertical vorticity ∂ζ/∂t. Their calculation expressions are as follows: .