Protection pad is aerifyd in exchange is become by pneumatophore, select switch, ball, one -way admission valve, one -way air valve group, the pneumatophore is from the appearance adoption is square, oval, circular, C appears or cavity shape, and the pneumatophore comprises several gasbag A, gasbag B, gasbag interval and breather pipe A, breather pipe B, select switch establishes to four selections, is equipped with 6 connectors, four selections will form the connection combination of four differences. Protection pad is aerifyd in exchange divides into two groups with the several gasbag, and the air that can carry on under the effect of external force between two group's gasbags exchanges, makes a set of gasbag surface rise, and the surface of another group's gasbag descends to two group's gasbags form the concavo -convex shape of protection pad, and the concave surface is the non - force of doing, and the convex surface reaches the purpose that the position was puted forth effort in the change for doing the force.