The diagnosis of tissue mechanical properties, e.g. vulnerability and viscoelasticity, has been being required clinically and cosmetically. Especially, the rupture of unstable plaque on coronary artery should cause acute coronary syndromes. Optical Coherence Straingraphy (OCSA) was proposed, which can visualize tissue mechanical information, e.g. strain tensor distribution, from speckle deformation between synthetic 3-dementional images obtained by Optical Coherence Tomography. This is basically constructed by Recursive 2- or 3-dementional cross-correlation as well as an image deformation technique which take account of linear deformation of interrogation volume. In this study, OCSA was in/ex vivo applied to finger pad of human skin and atherosclerotic plaque in WHHL rabbit aorta, respectively. Consequently, residual strain distributions identifi ed according to the mechanical boundary conditions of fingerprints and the accumulation of lipid tissue having low elastic modulus. It was concluded that 3D-OCSA could be highly effective to clinical tissue assessment as “Micro Mechanical Biopsy”.