A technique for non-contact optical measurement of in-plane displacements based on correlation analysis is presented. This approach can be used to identify the position of a marker before and after deformation of a specimen or plane test-object. Some mechanical parameters of materials and strains can be calculated using information from several markers’ displacements. The method is simpler than other optical techniques in experimental processing and can efficiently used to measure large deformations. The precision of marker identification method is analyzed. And some discussion on this method is also given.