Abstract: Aiming at the deficiency of the present parameters to measure target scattering randomness, a novel parameter is defined based on the degree of polarization of target scattering wave. Firstly, after the analysis of the relationship between the degree of polarization of target scattering wave and target scattering randomness, the novel parameter is constructed with the degree of polarization of target scattering wave. And then the feasibility of the novel parameter to measure target scattering randomness is clarified by the analysis of the behavior of the novel parameter as a function of the scattering order in volume backscatter or target anisotropy. As the new parameter involves simple operation, it overcomes the time-onsuming operation of the present parameters. With the experiment results of the real polarimetric SAR data of the typical areas of San Francisco and Flevoland, the rationality and practicability of this novel parameter are validated.