Abstract: In this paper the killing effects of thermo-chemo-radiotherapy were observed in Hela cells. Liner accelarator was used for the X-ray sourse. Cisplatin was used as the chemo-drug. The indexes used were the clone formative test and the cell cycle phase of flow cytometey （FCM）. The results demonstrated are as follow: （1） SF （survival fraction） by thermo-radiolherapy or thermo-chemotherapy was less than that by only single one. Thermo-chemotherapy was better than thermo-radiotherapy and triple treatment was most effective. （2） FCM showed that the cell cycle phase was sensitive to chemotherapy. When the drug dose was small, S+G₂/M multiplication cells increased and it had the stimulation reaction. When the dose was large, S+G₂/M cells decreased and it had inhibition reaction. In addition, there was no change at 24h in cell cycle phase by radio-hyperthermia and demonstrated that S+G₂/M multiplication cells increased lightly. It suggests that the chemo-drug dose should be reasonably large and radio-therapy should be repeated 24h later in clinical treatement.