The present invention relates to a method for selecting high-efficacy mesenchymal stem cells for use in treating an immune disease, the method comprising a step of measuring a level of a particular immunosuppressive biomarker in mesenchymal stem cells in which the expression or activity of suppressor of cytokine signaling (SOCS) is downregulated, high-efficacy mesenchymal stem cells selected by the method, and a method for treating ii an immune disease by using the high-efficacy mesenchymal stem cells. Providing a method useful for acquiring functionally excellent mesenchymal stem cells having an ability to control immune reactions for clinical treatment of various immune diseases including graft-versus-host diseases and autoimmune diseases, the present invention can find useful applications in the therapy of immune diseases.
