In this peper, we give an introduction to shearing speckle interferometry with double niterferences of the wave fronts. The information of the first inteference of the wave fronts before and after the deformation of the object is stored on two holographic plaids. the second interference is completed by using optical processing technique. The double interferences eliminate the influences of displacement and its first order derivative respectively, and so that the whole-field fringe pattern for second order derivative of the displacement is obtained.