Cancer stem cells are a subclass of stem-cell-like tumor cells.They have an apparently higher tumorigenicity than other cell populations within the same tumor.They play a Very important role in genesis,development and maintenance of cancer.The data from research in leukemia and solid timors suggest that in each cancer tissue,only a small fraction of the cells have the ability to initiate tumor,which are called cancer stem cells.In recent years,with in-depth research on stem cells and cancer stem cells,accumulating evidence suggests that cancer stem cells are the cause of malignant tumor metastasis and recurrence and are resistant current callcer drugs.Drugs targeting cancer stem cells are urgently needed. Flow cytometry and magnetic cell sorting using the identified tumor stem cell surface markers are mainly used to separate cancer stem cells or stem cell-like cells. In this article,the concept of cancer stem cells and the commonly used approaches to isolate and identify cancer stem cells,especially for gastric cancer stem cells will be reviewed.