Abstract: This paper briefly described the application value of this imaging method in the evaluation of active thyroid-related ophthalmopathy (TAO) by analyzing the different results of ⁹⁹Tc^m-diethylene triaminepentaacetic acid (DTPA) SPECT/CT orbital imaging in 2 patients and combined with literature review. At present, the commonly used clinical assessment of TAO active phase is mainly based on the clinical activity score (CAS) of the patient's symptoms, but the clinical manifestations of mild and moderate patients partially overlap, and it is not easy to identify using the CAS score alone, and the diagnosis is subject to a certain degree. The results of this study show that ⁹⁹Tc^m-DTPA SPECT/CT orbital imaging has a higher negative predictive value for inactive TAO than CAS, indicating that this imaging can also be an option for TAO assessment.