Thyroid cancer (TC) is an endocrine malignant tumor with the fastest-growing incidence worldwide. It has complex pathological types and significant heterogeneity, with great differences in clinical prognosis among different subtypes. Among them, aggressive subtypes, such as radioiodine-refractory (RAI-R) TC and anaplastic thyroid cancer (ATC), have become a major challenge in current clinical diagnosis and treatment, due to limited treatment options and high risks of recurrence and metastasis. Tumor metabolic reprogramming is one of the characteristics of cancer, among which the Warburg effect plays a driving role. As a rate-limiting enzyme in the glycolytic pathway, pyruvate kinase M2 (PKM2), with its unique functional plasticity, has become a linchpin of glycolytic metabolism and malignant phenotypes of tumor cells. This article will systematically review the functional regulatory mechanisms of PKM2, its specific role in TC, and explore the targeted therapeutic strategies and research prospects of TC with PKM2, providing a new theoretical basis and potential plans for the clinical diagnosis and treatment.