Scientific research shows that the development of cancer is closely related to psychosocial factors, and different psychological states can cause, cure and prevent cancer. According to research, emotional changes such as depression, isolation, jealousy, worry, sadness, impatience, irritability, long-term patience, grief due to loss of friends and relatives, suffering from blows, poor stimulation without relief, and long-term mental tension can contribute to the development of cancer. Traditional Chinese medicine emphasizes that “evil cannot be dried up when the righteousness is in the memory” and considers excessive stimulation of bad emotions such as joy, anger, worry, thought, grief, fear and fright as the source of all diseases, and takes psychological treatment as the first step to prevent and treat diseases. It is important to know that panic, worry and fear are in themselves a blow to the body’s immunity and their negative impact on human health cannot be underestimated. All cancer patients almost invariably have psychological disorders, which are diversified according to their personality, cultural cultivation and severity of the disease before falling ill. 70% of cancer patients have symptoms such as anxiety and depression; 30% have symptoms such as terror, depression, anger and despair, etc. These subjective fear and anxiety adverse psychological states are often the catalysts of cancer. Generally speaking, cancer has different psychological reactions at different stages, some of which are normal and adaptive, while others may be abnormal and maladaptive. Nearly 80% of advanced cancer patients are “scared” to death due to their excessive fear of the disease. On the contrary, patients who are able to deal with advanced tumors openly and actively cooperate with the battle against cancer can not only prolong their lives, but also face death calmly and peacefully. Therefore, psychotherapy is indispensable in the treatment of malignant tumors. Psychotherapy refers to the therapeutic process in which the therapist uses theories and methods of psychology to help patients overcome psychological barriers and improve their psychological state and behavior through the communication of language and behavior between doctors and patients as well as therapeutic interpersonal relationships. When a person is suffering from cancer is often the most mentally fragile time, human dignity is the most sensitive and easily injured. Psycho-behavioral intervention for oncology patients is a systematic project to influence patients’ behavior in coping with the disease through educational and psychotherapeutic means; its goal is to improve patients’ fighting spirit to overcome the disease, enhance self-esteem, improve coping ability, reduce confusion brought by the disease, as well as increase patients’ sense of control in fighting with the disease, and help patients better solve the problems they actually encounter. Tumor patients should believe that through reasonable, scientific, planned and appropriate comprehensive treatment, coupled with the positive cooperation of the patients, they can get through the difficulties of diagnosis and treatment and can fully embark on the road to recovery. They not only need sincere care, love, support, sympathy and understanding from family and society, but also should firmly believe that: ① cancer is not equal to death; ② cancer is an incurable disease, not an incurable disease; ③ cancer has a process of development, and treatment is to stop or delay its development; ④ science is developing, and there will be more and more treatment methods; ⑤ there will be miracles only with the belief of success.