The pressure of a certain airplane surface is calculated. Based on the superpose principle of current field, a two-dimension model with a planar point-fountain, a point-converge and a constant current of current field is established. According to the corresponding relationship between the main parameters of the model and the geometric parameters of the airframe, the model can be translated to three-dimension and expressed accurately. The rule of pressure distributing on the airframe surface can be gained from the characteristics of the current field. Finally, the contrast between the experiment and the calculation shows that the model and the procedure are exact, and the model can be used in a wide range.