Abstract: Occult thyroid carcinoma (OTC) is rare in differentiated thyroid carcinoma (DTC), and cases of OTC with extensive systemic metastasis are rarely reported at home and abroad. This paper reported a case of follicular carcinoma of thyroid with extensive metastasis from skeleton, lungs, adrenal gland and other parts of the whole body without primary focus, by analyzing the diagnosis and treatment process, laboratory examination, histopathological examination results and reviewing the relevant literature, the possible causes of OTC and the treatment scheme of extensive metastasis in the whole body were discussed.