The anisotropies of sheet metals are caused from the texture developed by a cold rolling process. The crystal grains in the texture take a partial direction, and the strength of the texture is different from that of the surrounding material. When the sheet metals are deformed with changes of the strain path, the difference of the strength brings a new texture and causes a new anisotropic principal axis. Therefore, it is supposed easily that the principal axis of anisotropies dose not behave like the material fiber printed on the sheet metals. To confirm the assumption, in this paper, a measuring method of revolution angles of principal axes is proposed by using a laser speckle strain meter. The revolution angle is measured by investigating the distribution of r-values with respect to the tension directions. Finally, a dynamical model of the principal axes is derived and its parameters are identified.