RFA is a minimally invasive in situ treatment technique, in which the electrode needle is inserted directly into the tumor tissue with the guidance of ultrasound or CT, and the high frequency conversion of RF current generated by the RF transmitter is introduced into the tumor tissue through the non-insulated part of the electrode needle, Through the frictional effect generated by the above two methods, the electrical energy is converted into heat energy, which increases the temperature of the tissue, and the local temperature can reach 90-120 ℃, thus causing thermal coagulation necrosis and denaturation of tumor cells; at the same time, the heat energy also induces apoptosis of tumor cells. Cells can still maintain normal function in an environment of about 40 ℃, but when the ambient temperature rises to 42-45 ℃, cells become sensitive to other damage factors such as chemotherapy drugs and radiation, and when the temperature rises to 50-52 ℃, it only takes a short time (4-6 min) to produce lethal damage to cells; between 60-100 ℃, it causes protein coagulation almost immediately, which makes the cytoplasmic enzyme structure, mitochondrial enzymes, and the tumor cells become dead. Between 60 and 100 ℃, it causes almost immediate protein coagulation and irreversible damage to intracellular enzyme structure, mitochondrial enzyme structure, and nucleic acid-histone complex in nucleus. Tumor tissues have a special sensitivity to heat, and this special sensitivity has its corresponding biological basis. Compared with normal tissues, the vascular network of tumor tissues is poorly developed, so that the blood flow in tumor tissues is slow and low, which is often about 10% of that of the adjacent normal tissues, thus leading to the reduction of its heat dissipation function and the accumulation of heat energy in tumor tissues. The effect of heat therapy increases with the increase of the proportion of oxygen-depleted cells; in the early stage of tissue stimulation by heat, blood vessels dilate, blood flow is accelerated, and tissue cell metabolism is enhanced, but then blood flow slows down and stagnates, acidic metabolites accumulate, and the pH value of the tissue decreases. The pH value in the tissue decreases, which increases the effect of heat therapy due to the increased sensitivity of cells to heat in the acidic environment. The mechanism of tumor cell damage caused by high temperature generated by RFA may also: 1. affect the structure and fluidity of tumor cell biofilm, thus affecting various functions of tumor cell biofilm. 2. 2.Increase the activity of lysosomes in tumor cells and destroy various cell organelles. 3.Kill the local tumor cells and coagulate the vascular tissues around the tumor to form an isolation zone, which helps to prevent tumor metastasis. 4.Inhibit the angiogenesis of tumor tissues and kill the tumor cells. 5.The thermal effect of RF can enhance the immunity of the body; the absorption process of necrotic material as the stimulation of endogenous thermogenic substances can stimulate the anti-tumor immunity of the body, and then improve the immunity of the body.