The Jinchiyuan and Zhangjiaba plutons are located to the north of Mianlue (Mianxian—Lueyang) suture zone in southern Qinling Mountains. The values of mean magnetic susceptibility Km are mainly less than 1000μSI, while corrected anisotropy degree PJ less than 1.1, which can be interpreted as flow magnetic fabrics. The shape parameter T of the magnetic susceptibility ellipsoid shows that the Jinchiyuan and Zhangjiaba plutons are respectively dominated by compressional and tensile deformation. However, it is obvious that most magnetic foliations of the samples on the margin are parallel to the boundary of the granites, and the inner ones are relatively disordered. The characters of magnetic fabrics reflect that the NNE—SSW compression still existed while the emplacement, but were much weaker than that of the main orogeny period, and magnetic fabrics of the two plutons are mainly formed in the lateral extrusion during the emplacement. This paper advocates that the plutons formed in the postcollisional tectonic environment after the closure of Mianlue (Mianxian—Lueyang) suture zone in Indosinian, and are the products of postorogeny while the tectonic regime changing from compressional to tensile.