Abstract: ObjectiveTo characterize the morphology of gastric cancer cell line SGC-7901 influenced by Cinobufacini,which is one of the traditional Chinese medicine reagents. The ultrastructure changes of gastric cancer cell line SGC-7901 interacted by Cinobufacini were analyzed by atomic force microscope (AFM) at single-cell level. MethodThe ultrastructure changes of gastric cancer cell line SGC-7901 interacted by Cinobfacini were analyzed by atomic force microscope (AFM) at single-cell level. And cell apoptotic rate was determined by flow cytometry. ResultCompared to the untreated cell,the size of cells decreased,and the nucleolus crimpled. The cellular membrane ultrastructure,Rp-v,Rq,and Ra value were significantly changed. And flow cytometry data indicated that cell apoptosis rate increased with increasing concentration of Cinobufacini. ConclusionAFM-based experiments which helped us increase the awareness of gastric cancer cell line SGC-7901 at visualization will contribute to shedding new light into the structure-function relationships of cell surfaces at single cell or nanometer level. In other words,AFM could be a new useful tool to diagnose cancer at single cell level.