Abstract: 【Abstract】Thyroid associated ophthalmopathy (TAO)  is an autoimmune disease, it’s pathogenesis related to the inflammation caused by reaction between T cell and orbital fibroblasts, and adipogenesis is an important pathological procedure. Cyclooxygenase2 (COX 2) is an important proinflammatory factor associated with inflammatory process of various autoimmune diseases. Recent studies have shown that COX2 plays an important role in TAO orbital fat proliferation. Activated T lymphocytes in the orbit of TAO patients overexpress COX2, which could induct the differentiation of CD90- orbital fibroblasts into mature adipocytes through combination with peroxisome proliferator activated receptor γ (PPARγ) expressed on the surface of CD90- orbital fibroblasts, thereby promoting the occurrence of orbital fat proliferation. (Int Rev Ophthalmol, 2012, 36: 336340)