Cancer patients often have decreased appetite due to the influence of disease factors and treatments methods such as surgery radiotherapy and chemotherapy. The lack of nutritional intake caused by decreased appetite may result in malnutrition and cachexia which in turn reduces the tolerability and efficacy of anticancer treatments leads to decreased quality of life and severely affects prognosis and survival of cancer patients. Accurate evaluation of patient􀆳s appetite and combined with nutritional risk screening and nutritional assessment during the course of the disease can identify the patients at nutritional risk as early as possible and give individualized nutritional support which is beneficial for improving appetite and nutritional status preventing or delaying the progression of the disease course and increasing treatment tolerability. It is of positive significance to improve the prognosis and quality of life of patients. In order to standardize the nutritional diagnosis and treatment of cancer patients with decreased appetite and improve the treatment effect this expert consensus is presented based on the existing research findings at home and abroad combining the expert opinions and clinical experience to elucidate the definition and mechanism of loss of appetite in cancer patients and provide appetite assessment tools such as anorexia / cachexia subscale appetite and symptom questionnaire and appetite scale and then give nutritional recommendations for cancer patients with poor appetite. We hope that the consensus release can improve the identification evaluation and nutritional treatment of cancer patients with decreased appetite by clinical medical staffs and clinical nutritionists and increase the clinical benefits of the patients.