Abstract: According to the thermodynamic properties of rubber balloon and the theory of Mooney model，we derive the relationship between the additional pressure and the radius of rubber balloons' membrane during inflation and deflation when two balloons are connected，and the relationship between the two connected balloons' volume changes and internal pressure is also obtained. The theoretical results are in agreement with the experimental results. Applying the model into the research of the simple model of the hovercraft，we take use of the experimental results to modify the theoretical model.

Key words: rubber balloon, thermodynamic properties, Mooney model, hovercraft