Abstract: Objective:The aim of this research was to study the classification of SYT-SSX fusion genes in synovial sar -coma (SS) and to investigate the function of these fusion genes in the cell cycle. Hopefully these results will elicit a novel path to discover the function of the fusion genes in SS. Methods:RNA was extracted from54paraffin embedded SS tis-sues known to express SYT-SSX fusion genes. RT-PCR was used to classify the type of fusion gene in each tissue as ei ther SYT-SSX1 or SYT-SSX2. The typical parameters were used to manufacture the tissue microarray. The expression lev -el of CyclinD 1, CDK 4, p21WAF1/CIP 1 and p27were examined by immunohistochemistry. Labeling index was used to eval-uate the entire staining status of each slide.Results: Of the 54patient tissues, there were22(40.74% ) cases with type SYT-SSX1 fusion gene and 32(59.26%) cases with type SYT-SSX2 fusion gene. Significant differences in the expression levels of CyclinD 1, CDK 4, p21WAF1/CIP 1 and p 27were seen between the different types of fusion genes (P<0.05). Conclusion: The proliferation index of SSX1 is higher than that of SSX 2. The fusion gene of SYT-SSX 1 could increase the ex -pression of CyclinD 1/CDK 4 genes and decrease the expression of p21WAF1/CIP 1 and p 27genes. We hypothesize that SYT-SSX1 and SYT-SSX2 may differ in transcriptional deregulation of one or more key genes involved in the regulation of mesenchymal cells to switch on the cell cycle and escape the mechanism of supervision.