This project is to study the constitutive relationship of shape memory alloy(SMA) with initial texture. The NiTi alloy is chosen for study both theoretically and experimentally. Three kinds of sampels, i.e. sheet, tube and wire, which are prepared by different method to produce different textures, are selected. The experiments are carried out with different method for different kinds of samples. The goal of each experiment is to get the orientation distribution function and the corresponding stress-strain curve of the sample. Based on the Eshelby solution in anisotropic problem and the thermodynamic principle, the constitutive relationships of the single crystal SMA and polycrystallin SMA will be constructed. In practice, polycrystalline NiTi alloy are often used.The texture in the material can not be avoid in its preparation,such as the bone plate used in bone broken surgery and the stent. Therefore this project has not only the practical background but also the theoretical background.