Abstract: The present invention relates to a fusion protein composed of the extracellular domain of PD-L1 and a modified immunoglobulin Fc region. The extracellular domain of PD-L1 and a fragment thereof have excellent immunomodulatory activity, and can be used as an immunomodulatory agent if a modified immunoglobulin Fc region is coupled thereto. Accordingly, the PD-L1 fusion protein according to the present invention demonstrated its excellent effect in disease models of inflammatory bowel disease, colitis, psoriasis, asthma and arthritis, and thus can be very effectively used for the treatment of such diseases.