Abstract: Objective : To investigate the clinical features and evaluated the prognostic factors of primary squamous cell carcinoma of thyroid(SCCT). Methods : Clinical features including sex, age, size,metastasis, operation, chemotherapy and radiotherapy of 27 cases of SCCT patients treated in our institution during 1969 to 2000 were retrospectively reviewed and evaluated using SPSS10.0 statistical software package. The rate of survival is computed and compared with the life table and the log-rank test of the Kaplan-Meier analysis. The COX regression model is processed by the method of the stepwise regression analysis when the factors are significant. Results : The incidence of primary SCCT is rare, but highly aggressive. The operations mode and the radiotherapy are the independent factors that could influence the prognosis separated or combined. Conclusion : We suggest that extensive resection of the tumor and post-operation radiotherapy is the recommended treatment to the SCCT.