Abstract: It is efficient to decrease the resistance of sliding plate on moist and soft soil by airing method,and the rate of resistance decrease is dependent on the pressure, thickness and width of airflow layer between the sliding plate and the soil. A mathematical model is put forword which can be used to predict these parameters of the airflow layer,and it is verified by experiment. The results of both calculation and experiment show, that the farther from the air injecting hole, the thinner the airflow layer is. Also, the thickness and the pressure of the airflow layer increase with the increase of the discharge.