Abstract: A three-dimensional cloud-scale model has been designed. The governing equa-lions of model are composed of compressible motion equations, continuity equa-lion, pressure equation, thermodynamics equation, those are of Euler type, and cloud-precipitation microphysics equations, those are of Lagrange type. In the solving governing equations the splitting procedure has used, the both mesh of general and staggering have been structured, the integration schemes have adopted the Eulerian backward difference method for the general mesh and semiimplicit method for staggering mesh. Several experiments of modelling have fin-fished and the results have shown a reasonable three-dimension image for deep convection. Using this model the effects of horizontal vortex circulation follow-ing the vertical one on the formation and developing of downdraft airflow within cloudy domain have been studied.