The propagation characteristics of spectral degrees of cross-polarization (SDCP) of quasi-homogenous(QH) beams are studied based on the unified theory of coherence polarization and generalized Huygens-Fresnel principle.The characteristics of SDCP changing with propagation distance of different points in the field are obtained.The results show that the quasi- homogenous sources which have same changes of the degree of polarization（DOP）of each position point may have different changes of SDCP between two spatial points.They may increase or decrease with propagation distance increases depend on the distance of two position points due to the perturbations of turbulence,it will have the same value in a special distance,and then will deviate from each other when propagation distance increases continuously.The degree of coherence and the correlation of intensity fluctuations have different characteristics of variations.The results obtained reveal close relationship between high order statistic properties of optical beam field.The physical significance of SDCP will be the foundation of applications like correlation imaging and polarization communications in free space or atmosphere.