A slip-line field theory of transversely isotropic body is proposed in the presentpaper in order to deal with problems in geology and geotechniques.The Goldenblat-Kopnov failure criterion is employed.The parameters in it are treated as functions of tempperature It is applicable to transverse isotropic media in nonuniform temperature field.The basic equtions of plastic deformation are developed while the associated rules of flow are derived.By means of characteristic line theory,slip-line slope formulas and laws of variation of stress and velocity along slip lines are obtained,The indentation on semi-infinite media is calculated.The theory developed in this paper may be simplified into many classical theories such as Mises,Hill,and Coulomb ones,This complicated theory may be applied to geotechniques,geological structures,petroleum industry,mining engineering,etc.