Speckle interferometry with phase shifting method is used to measure in-plane displacements of a steel plate with a partly through-thickness circular hole and a steel plate with a through-thickness circular hole. The circular hole of steel plate with a partly through-thickness circular hole is cut on the rear side of the plate, so that it is not visible during experiment. The speckle noises of fringe patterns acquired by optical experiment are processed with image processing algorithm of Gaussian blur and the in-plane displacements of the two specimens are obtained by use of the processed fringe patterns. Also the in-plane displacements of the two specimens are calculated by use of ANSYS. The results of optical experiments are quite comparable to those of calculation with ANSYS.