Cancer-related anorexia is defined as decreased desire to eat, resulting in reduced food intake and/or weight loss. Anorexia is prone to occur in patients with cancer, leading to reduced quality of life, decreased treatment tolerance, reduced the effect of treatment and increased risk of mortality. Therefore, correct understanding, evaluation and intervention of CA are indispensable in the treatment of cancer. In this review, the pathogenesis of anorexia tumor, diagnosis, evaluation, treatment and follow-up were discussed. Cancer anorexia is closely related to factors of tumor disease, gastrointestinal dysfunction, delayed gastric emptying, and poor absorption caused by tumor or various adverse reactions of anti-tumor treatment. Tumor tissue releases the active substances that cause anorexia into the circulatory system or the tumor itself induces metabolic abnormalities that cause the host tissue to release appetite suppressor factors. Accurate assessment of CA is based on related symptoms such as change in taste, nausea, early enough, combined with the appetite symptoms scale (commonly used with “symptom-based assessment” questionnaire and the visual analogue scale for diagnosis, and comprehensive evaluations of nutrition status, oncology and psychology. The PG-SGA method is recommended for nutritional assessment, following the triple diagnosis model of malnutrition. Psychological evaluation contains observation, interview, and psychological tests. The symptom checklist (SCL-90) is recommended. The purpose of the treatment is to improve the eating status and clinical manifestations of malnutrition, ensure the uptake of energy and nutrients in cancer patients, and improve patients’ immunity and the tolerance of anti-tumor treatments. Treatment needs more than one mode, including antitumor/ symptomatic treatment and the elimination of anorexia, stimulates the appetite and drug treatment for inflammatory factor, nutritional metabolic therapy and bowel function adjustment, exercise and psychological emotion regulation of a variety of treatments. Patients with CA need regular follow-up and evaluation, including laboratory parameters, nutritional status, oncology and other indicators. Guidance and treatment will be adjusted according to the follow-up situation.