Objective To study the lethal cause of thyroid malignant tumor postoperation.Methods The clinical condition, pathology of 356 cases and follow-up data of 227 cases of thyroid malignant tumor postoperativly during 32 years was comprehensively analyzed.Results The survival rates of 3-year, 5-year and 10-year in 227cases of thyroid malignant tumor were 91%, 83% and 80.2%, respectively. The dead cases was 19.8%(45/227),84.4%(38/45) dead in 5 years after operation. The mortality of differentiated cancer was 1...