The present invention relates to a stabilized pharmaceutical preparation of R27T, the preparation comprising a human interferon beta variant (R27T), an acetate buffer, arginine, trehalose, Poloxamer 188, and methionine. The stabilized R27T pharmaceutical preparation according to the present invention is obtained by the development of a preparation having a novel composition through the substitution of mannitol with trehalose in the composition of a preparation containing mannitol, which was previously studied by the present inventors. It was confirmed that the preparation can remedy a disadvantage of the protein aggregate increase due to the mixing and addition of mannitol and arginine HCl and can improve thermodynamic/structural stability and the resulting stability during the long-term storage, and thus it is expected that the preparation can be advantageously used in the prevention, alleviation, and treatment of multiple sclerosis, cancer, autoimmune diseases, viral infectious diseases, HIV infectious diseases, hepatitis C, rheumatoid arthritis, and the like.
