Abstract: Kinetic energy budget of sub-synoptic scale disturbance which produces heavy rainfall during Mai-yu season is computed by using conventional rawinsonde and height data.The main results of this study are as follows:1) In the calculation of kinetic energy,divergence part of the wind cane't be neglected; 2) Kinetic energy is exported from the disturbance toward the surrounding atmosphere; 3) The rate of kinetic enemy generation by rotational wind is negative,while that of divergence wind is positive in the upper and Lower troposphere.The summation of two parts is still negative,then the subgrid scale kinetic energy exchange exerts a significant effect on the kinetic energy budget of the disturbance.In other words,moist convection developed in conditional unstable atmosphere is an important process in moist baroclinic atmosphere.Hence,probably this is a proof of the importance of role of water vapor in the motion of the atmosphere.These results are helpful to understand the mechanism of this disturbance and to improve the design of numerical model.