The existence of malignant stem cells has been proven for hematopoietic disorder as well as some solid tumors. Although significant improvements in cancer therapy have been made, tumor recurrence is frequent and can partly be due to the absence of therapeutic target which tumor stem cells are regarded as. In this paper we shall explore different therapeutic scenarios for successful tumor treatment by using a predictive mathematical model based on the cell compartment method. In particular, we shall study the effects of the chemotherapeutic target rate and of the interval of G-CSF administration on therapy for myeloid malignancies through simulating chemotherapy with G-CSF (granulocyte colony-stimulating factor) support. The results indicate that if target rate is raised to an enough high value, the efficiency of chemotherapy increases so greatly that the tumor mature cells perish completely and normal mature cells are maintained at a normal level. Furthermore, the administration of G-CSF can increase the amount of the normal mature cells to a normal level. However, too long interval of G-CSF administration is demonstrated not propitious to patients' healing. These results indicate that the simulations may be an effective approach to help designing therapeutic scenarios for successful tumor treatment by chemotherapy.