This article reports the clinical data of a patient with anti-Hu-positive paraneoplastic syndrome combined with Guillain-Barré syndrome （GBS）. The male patient， aged 71 years， had the clinical manifestation of the acute onset of tetraplegia， and testing and examination results were consistent with syndrome of inappropriate antidiuretic hormone secretion and GBS. Serum anti-Hu antibody was positive， and PET-CT screening considered the possibility of lung cancer； finally small cell lung cancer was confirmed by pathology. The patient was improved slightly after the administration of hormone， cyclophosphamide， and oncological therapy （etoposide+cisplatin）， but then his conditions progressed and worsened， and finally the patient died due to respiratory failure. In clinical practice， the possibility of this disease should be considered for middle-aged or older patients with peripheral neuropathy or intractable hyponatremia as the main manifestation， which cannot be completely explained by other diseases， and such patients need to be screened for occult tumors. ［Journal of International Neurology and Neurosurgery, 2022, 49(6): 65-69］