Extraskeletal Ewing sarcoma is a rare event, and extraskeletal Ewing sarcoma of the thyroid gland is even rarer. It has non-specific clinical manifestation and difficulty in early diagnosis. The diagnosis mainly depends on histology and immunohistochemistry. It possesses the features of high malignancy, high rate of local recurrence, and distant metastasis. Currently, the aggressive multimodal treatment contains surgery, chemotherapy, and radiotherapy. This study presented a case of extraskeletal Ewing sarcoma arising in the thyroid gland of a 30-year-old woman, who presented with supraclavicular mass and sense of dysphagia obstruction in Department of Otolaryngology, Head and Neck Surgery, Second Xiangya Hospital, Central South University in 2018. Imaging studies demonstrated a cystic-solid mass in inferior of the left leaf of thyroid gland and in the posterior of the trachea and esophagus. The patient underwent localized tumor resection. The pathological diagnosis revealed that it was a small round cell tumor, and the immunohistochemistry results were considered to be extraskeletal Ewing sarcoma. Subsequently, the patient was given chemotherapy and local radiation therapy. There was no evidence of tumor recurrence or metastasis.