Abstract: A heat transfer model is presented for the hyperthermia treatment of cervix cancer using an intracavitary microwave applicator. The specific absorbtion rate (SAR)distributed for the transvaginal probe is measured in a phantom. On this basis, the 3-D finite element simulation of the temperature field is conducted. And the results figured out through programming are compared with that from commercial software called ANSYS. Besides in terms of clinical practice the variations of the parameters are studied, involving the varieties of tumor shape and size, blood perfusion, etc. Finally the theoretical basis and some significant conclusions are presented for clinical application.