Abstract:By using hourly Tbb data, lightning data, rainfall observations from a utomatic weather stations, the mesoscale characteristic of a torrential rain in Sichuan and Chongqing during July 16-20, 2007 was analyzed in order to obtain va luable information on evaluating and predicting such case of torrential rain. Th e study shows that this case was a coupling result of two mesoscale systems whic h are Plateau Vortex and Southwestern Vortex. The strong and thick positive vort ex column and the accompanying updraft are the main factors, which cause the con vection bodiesgenerate and eliminate in turn and lead to torrential rain to occ ur repeatedly in the nearby area. Three mesoscale cloud systems (MCS) in the sou thwestern vortex initiate the heavy rain directly. In this case, generation and elimination of the MCS and the convective clouds in the western Tibetan plateau performed in a way of seesaw. The movement direction of lightning can represent the direction of movement in strong convection zone, which is also the direction of movement of heavy rainfall in the future. The emergence of lightning is befo re the precipitation, a sudden increase or decrease of lightning have a certain significance to the increase or decrease of precipitation in the future.