To study the definition, etiology, diagnosis, treatment and prognosis in patients with multiple primary malignant tumor of upper aerodigestive tract cancer and thyroid cancer.,Retrospectively analyze the events of 7 cases with multiple primary malignant tumors of upper aerodigestive tract cancer and thyroid cancer.,Lesions of upper aerodigestive tract cancer and thyroid cancer located on the same side. After 4 to 8 years of follow-up, 2 cases of hypopharyngeal cancer and thyroid cancer got poor prognosis, prognosis of other patients with early stage laryngeal cancer and thyroid cancer is better.,The prognosis of multiple primary malignant tumors in patients with upper aerodigestive tract cancer and thyroid cancer depends on the biological behavior of aerodigestive tract cancer.