Abstract: Synoptic-scale variables are used to determine the vorticity budget in the heavy precipitation region during the Mei-Yu season. In this region there exists a norticity accumulation in the lower half of the troposphere and a sink in the upper-troposphere. This result implies that connective-scale motion exert a significant.effect on the vorticity budget and suggests that in the modelling of the summer precipitation weather systems, attention must be given to parameterizing connective. effects in the momentum equation as well as in the thermodynamic energy and water mass continuity equations. A vorticity parameterization scheme for cumulus convection is derived by using a one dimensional steady cumulus model. The result is compared with that determined by synoptic-scale variables.