Abstract: Loss of appetite is one of the common symptoms of cancer patients, which can lead to the reduction of food intake and decrease of nutritional status and body immunity thereby affecting the therapeutic effect and tolerance abilities of patients, and increasing the risk of adverse reactions in patients with tumor. In the process of anti-tumor treatment, scientific appetite assessment and effective nursing intervention are helpful to further provide comprehensive, whole process and individualized nutrition management, improve patients' qualities of life and increase the chance of successful treatment. This study clarified the concept and performance of loss of appetite in tumor patients by consulting domestic and foreign literatures, introduced the tools for evaluating appetite of cancer patients and analyzed its influencing factors, and elaborated the main nursing intervention measures for loss of appetite in tumor patients in order to provide references for clinical practice and researches of improvement of loss of appetite in tumor patients.