In our daily life, people often talk about cancer. Once a person suffers from cancer, it means that his or her life will be terminated soon, but what makes people fear more is the pain that cancer brings to the patient’s life. Statistics at home and abroad show that the incidence of pain associated with cancer patients increases and worsens progressively with the progress of the disease, and about 50% of all cancer patients have different degrees of pain, and 70%-90% of patients in advanced stages experience pain. Foreign studies have found that about 70% of cancer patients have pain that affects function, such as sleep,, activity, mood and recreation. Persistent severe cancer pain is the main cause of depression, and 80% of cancer patients with suicidal tendency are related to severe pain. So how to properly understand and face cancer pain? Generally speaking, the causes of cancer pain are divided into the following three situations: (a) pain directly caused by cancer, which accounts for about 70%-80% of cancer pain; (b) pain caused by cancer treatment (such as chemotherapy, radiotherapy, invasive examination, venipuncture, etc.), which is about 10%-20%; (c) chronic pain indirectly caused by cancer (such as back and leg pain , arthritis, herpes zoster, etc., which is about 5-10%). In clinical work, we should understand and analyze the causes of cancer pain, assess the patient’s cardiopulmonary function and the presence of liver and kidney function damage, and then reasonably choose the treatment method according to the pathological mechanism of cancer pain to achieve the target. Experts from the International Health Organization believe that cancer pain is a disease, not just a clinical symptom. Cancer pain is the most complex pain problem, and the pain caused by it will change due to the progress of cancer disease, and the pain will also change due to the body structure and organ dysfunction. Some patients with cancer pain from bone metastases have limited limb movement, pain worsens after activity, and quality of life decreases sharply. In addition, pain affects patients’ physiological functions, weakens the body’s ability to resist disease and accelerates the growth of tumors. The literature shows that persistent unrelieved cancer pain can significantly shorten the survival time of patients. Therefore, controlling cancer pain is a very important part of cancer treatment, in a sense as important as surgery, radiotherapy and chemotherapy. Especially at the advanced stage of cancer, effective elimination of cancer pain is the most urgent requirement of patients, and it is even more relevant than anti-cancer treatment. The effectiveness of cancer pain treatment often depends on the knowledge, confidence and attitude of patients, their families, and health care workers towards pain control. Pain management is a marginal discipline that has gradually gained attention in recent years. Clinicians rarely receive training in pain management and lack sufficient knowledge of cancer pain management methods, and some healthcare professionals tend to ignore the existence of patients’ pain and believe that some pain is inevitable, unnecessary or uncontrollable. Patients and family members lack accurate medical knowledge and often mistakenly believe that cancer pain is inevitable and difficult to treat, and more often refuse to take medication or take insufficient amounts of medication for fear of opioid addiction. Some patients use analgesic drugs only when the pain is aggravated and stop taking them once the pain is relieved, which makes the pain treatment less effective. The main methods of treating cancer pain are the three-stage drug therapy promoted by WHO and the four-stage therapy including nerve destruction and intrathecal drug delivery. If the route and method of drug delivery are correctly selected, the standardized drug use and reasonable treatment can significantly relieve the pain of about 70-90% of patients. In conclusion, cancer pain is the main reason that threatens the normal life of patients. The mechanism of cancer pain is complex, pain is intense and variable, and treating cancer pain treatment in an abandoned way often leaves patients in extreme pain and lose confidence in life. We should pay attention to the pain-related problems of cancer patients, recognize cancer pain as a disease, give cancer pain treatment the same or higher status as oncologic surgery, chemotherapy or radiotherapy, and care for the physical and mental pain of cancer pain patients in a humanistic way. It is the duty of pain specialists to effectively control cancer pain and improve patients’ quality of life, which is the basic right of patients!