To develop the satellite cloud image interpretation skills and adequately exert the role of satellite cloud image in the forecast for regional rainstorm, some typical features of water vapor images during different phases of the rainstorm and their physical meaning are interpreted preliminarily, and satellite cloud image interpretation skills suitable for regional rainstorm in China are explored by analyzing FY2C water vapor images integrated with conventional dynamics fields and potential vorticity field for the rainstorm over Changjiang and Huaihe River Valley in 9-10 July 2007. The typical rainstorm event validates the good corresponding relations between satellite water vapor images and circulation and potential vorticity fields in the mid upper troposphere. According to these relations, 4 water vapor image indicators with certain forecasting meanings are summarized and abstracted: a “dry triangle structure” induced by jet breaking and wind shear, a large scale tundish like shape cloud system resulting from southward intrusion of dry and cold air, a leaf like cloud induced by dry intrusion of cold air, a white slender strip cloud line symbolizing the generation of a new jet core, etc. These features and indicators have definite physical meanings and good indicating roles for rainstorm forecast, and are easy to be identified and applied.