Soft tissues of human and animals are composite, typically being made up of the collagen and elastin fibres with high water contents. The strain measurement in soft tissues has proven to be a difficult task. Digital Speckle Method, an optical measurement method combining with computer image processing technique, has many advantages like full-field, non-contact and high measuring accuracy. Two main techniques, the Digital Speckle Correlation Method (DSCM) and Electric Speckle Pattern Interferometry (ESPI), have been developed and applied on many aspects. Using these two methods, the strain measurements caused by the continual deformation of soft tissues under pure tensile loading are completed and presented in this paper. Experiments are performed under the conditions of constant temperature and necessitate humidity with smart sensor. After capture a series of speckle patterns in continual time period, the displacement and strain distribution of soft tissues can be obtained by two improved techniques (Improved DSCM and Time-Sequence ESPI). Thus, the tensile modulus and Poisson ratio of soft tissues will be extracted.