Abstract: It was believed that metabolic changes of with in cancer nuclei result from the killing effect of high temperature on cancer cells, such as metabolic changes of RNA, slowing down of the speed of synthesis, disturbance in the synthesis of RNA and proteins, the 1oss of the cells ability to proliferate . Now the idea doesn's seem comprehensive enough, for normal tissues also under 90 the above ehange . Exeri-ments show that high temperature affects cancer cells selectively, enhancing sensi-tivity. The heating method includes general, regional and local heating. Local heat-ing usually uses instruments equipped with electric fields with low frequency and high frequency, ultrosonic waves, mierowaves or short waves to heat the tumor di-rectly. The method is endowed with the ability to restrain cancers selectively, and avoids the untoward effects of general and regional heating. The 30 cases analysed in this paper of malignant tumor metastasis in the neck show that treatment with thermotherapy combined with radiotherapy achieves better therapeutic effects than those treated with radiotherapys only.