The 180 degree back scattering character of biologic tissue and other turbid mediae can reflect the media′s information inside. Regarding turbid media as a "Black-box", the back scattering characteristic parameters for linear-polarized light in trubid media can be expressed by a polarization plane rotation angle α, polarization maintaining factor β and reflectivity r. A schematic of the measurement about the characteristic parameter was designed. And the milk′s deionized water solutions with different concentration were measured. When the concentration is 25%, α=3°, β=0 15, r=0 09. When the solution′s concentration is changed, the three parameters will be changed, too.