Objective To analyse the clinicopathological characteristics of synovial sarcoma (SS) from histomorphology,immunohistochemical (IHC) and fluorescence in situ hybridization (FISH),and to investigate the related factors influencing the prognosis of SS patients.Methods 94 cases were collected,including 60 SS cases and 34 in dined to SS cases.The expressions of common antibodies related to the diagnosis of SS Vimentin,CD99,AE1/AE3,EMA,CD34,Calponin,Ki-67 were detected by IHC,and the SYT-SSX fusion gene was detected by FISH.The clinical pathologic factors that affecting the prognosis of patients were analyzed through the statistical method.Results The positive rates of Vimentin,CD99,AE1/AE3,EMA,CD34,Calponin,Ki-67 were 100.00 ％,74.47 ％,36.17 ％,28.72 ％,17.02 ％,90.43 ％ and 60.64 ％ respectively.FISH results showed that 81 patients were tested with SYT gene translocation,including 54 cases who were considered as SS,and 27 cases who were suspected/inclined to SS,and the number of positive cells surpassed 80 ％.The gene translocation was not related with the patient' s age,sex,tumor position,histological type,differentiation of the cancer (all P ＞ 0.05).Single factor survival analysis showed that the degree of differentiation,tumor diameter,the recurrence and metastasis had certain influences on patients' survival time (all P ＜ 0.05).Multiple factors regression analysis showed that the degree of differentiation and tumor diameter were the risk factors influencing the prognosis of SS (risk coefficients ＞ 1,P ＜ 0.05).Conclusions IHC combined with FISH SYT-SSX fusion gene detection have the vital significance in the diagnosis of SS.The degree of differentiation and tumor size are the risk factors influencing the prognosis of SS.