.To explore the common syndrome distribution characteristics in thyroid-associated ophthalmopathy(TAO) and provide a basis for syndrome differentiation and treatment in traditional Chinese medicine(TCM).Methods:Four-diagnosis information from patients with TAO at the First Affiliated Hospital of Henan University of Chinese Medicine was collected to establish a clinical database.A hidden structure model was constructed using Lantern 5.0 software，and comprehensive cluster analysis was performed to identify common syndromes of TAO.SPSS 25.0 software was used for factor analysis and hierarchical cluster analysis to infer potential syndrome types.Syndrome classification was finalized through integrated analysis.Results:A total of 621 TAO patients and 94 symptoms were included.Fifty-five symptoms with frequencies≥41 were used to construct a hidden structure model，yielding 20 hidden variables and 6 common syndromes via clustering.Nineteen common factors were extracted from factor analysis of symptoms with frequencies≥6%，and these common factors underwent hierarchical cluster analysis to infer eight common syndromes.By combining results from both analytical methods and expert knowledge，six common syndromes were ultimately identified.Conclusion:The six common syndromes of TAO are liver and gallbladder dampness-heat syndrome，liver fire hyperactivity syndrome，liver depression and qi stagnation syndrome，deficiency of the heart and spleen syndrome，qi stagnation and blood stasis syndrome，and deficiency of the liver and kidney syndrome.These findings can provide a reference for syndrome differentiation and treatment of TAO in TCM