Abstract: Abstract：The parameters of magnetic fabrics of deformed rocks such as Kmax, Kint, Kmin, P, T, F, L and E can be used to quantitatively display the behaviors of tectonic deformation. Characteristics of magnetic fabrics of the ductile shear zone in Sandaogou area of Inner Mongolia were analyzed in this study. The results show that most E values are larger than or close to 1; T values larger than 0 are more than those smaller than 0; P values are larger than 1, and the data in graphic variant Flinn of the L-F parameters of magnetic fabrics are concentrated in the shear zone and the compression zone. It is indicated that the magnetic susceptibility ellipsoid mainly finds expression in flatted ball ellipsoid whose foliation is more developed than lineation. The rocks in Sandaogou ductile shear zone experienced a strong tectonic activity of extrusion shear mechanical mechanism.The stress, strain and deformation characteristics are consistent with field features and microstructure.