Introduction: Depression is like a “mental cold”, it develops slowly and needs to be managed slowly. For some cancer patients, negative emotions exist only for a few days to a few weeks after diagnosis, after which they will slowly adjust and subside; while other patients will gradually develop depression. Depression can cause long-term negative emotions in patients, reducing their quality of survival and compliance with treatment, and ultimately affecting their survival time. However, depression is often overlooked by doctors and patients in the general medical process, especially in cancer treatment. What should oncology patients with depression do? I. Antidepressant medication Surveys show that antidepressant medication is effective for 70% of depressed patients. Critics of pharmacotherapy believe that antidepressant medication only eliminates the patient’s depressive symptoms and fails to treat the patient’s underlying incongruent cognitive structure. Its proponents, on the other hand, argue that depressed patients’ pessimistic, negative thoughts are the result, not the cause, of depression and that the application of pharmacotherapy can remove these negative dysfunctional attitudes. In recent years, research on antidepressant drugs has progressed faster, and more new drugs have been developed with more reliable clinical effects. Psychotherapy Psychotherapy can not only reduce depressive symptoms, but also reduce some other psychosocial impairments of patients, improve their psychosocial functions, and prevent the recurrence of depression. Although psychotherapy has a slower onset than medication, some studies have shown that in practice, psychotherapy has fewer adverse effects than medication, so patients’ acceptance of psychotherapy is more durable, resulting in less risk of relapse when patients stop treatment than medication. The main psychological therapies for depression include interpersonal therapy, cognitive-behavioral therapy, family therapy, etc., and various psychological therapies are often applied in combination. Third, other adjuvant therapy Clinical practice shows that reading therapy, music therapy are effective adjuvant treatment for depression. Relaxation training, physical exercise, writing, yoga and other activities that make patients feel a sense of self-control are also helpful in the adjunctive treatment of mild to moderate depression. A British survey showed that only half of cancer patients with major depression discussed their low mood with their family doctor; one-third of patients received antidepressant medication, with very few patients adhering to a full dose and course of treatment; very few patients received psychotherapy or sought help from mental health services; and most patients received ineffective treatment. Conclusion: Studies have shown that depression can reduce the effectiveness of cancer treatment, increase the cost of treatment and jeopardize patients’ quality of life, and severe depression is even an important indicator of suicidal tendency in cancer patients.