Subacute thyroiditis (SAT) is a thyroid inflammatory disease, which can be triggered by viral infection. The severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) is considered to be a potent SAT-triggering factor in this COVID-19 pandemic. However, SAT occurring after SARS-CoV-2 vaccination is rarely reported. Despite the high availability of diagnostic tools, the recurrence and steroid dependence as well as delayed diagnosis of SAT remain. This paper reports a rare case where a patient was diagnosed with SAT post receiving a recombinant novel coronavirus vaccine (Anhui Zhifei Longcom Biopharmaceutical Co.Ltd., China), and efficiently treated with traditional Chinese medicine rather than prednisone. We hope that this case report not only contributes to raising awareness of SAT related to the COVID-19 vaccine but also provides an effective remedy in addition to glucocorticoid (GC).