Abstract: In this work，mutations of c-Ha-ras gene in 20 cases of primary gastric cancer were investigatedby using restriction fragments length polymorphism (RFLP) and single-strand conformation poly-morphism (SSCP)analysis of the polymerase chain reaction product. We found that these two meth-ods were highly simple，rapid and sensitive assay system for detecting c-Ha-ras gene mutations oflarge number of tumor samples and PCR-SSCP could also detect c-Ha-ras point mutations in severalcodons at same time.