The study of nutritional risk and malnutrition of tumor patients increased year by year, which has drawn more and more attention both at home and abroad. Clinical trials showed that cancer patients usually suffered from nutritional risk and malnutrition in China, and the incidence could be 40%~80%, incidence of malnutrition and nutritional risk is higher in patients with advanced malignant tumor. Nutritional risk and malnutrition produces seriously influenced tumor patients’ prognosis, reduced the tolerance and sensitivity of surgery, radiotherapy and chemotherapy, lowered the quality of life and overall survival time. Effective nutritional therapy shortened the length of hospital stay, lowered incidence of complications and hospitalization costs upgraded the quality of life, decreased morality and increased survival time. Tumors in patients with clinical nutrition therapy had become increasingly important, active and effective intervention in patients with malignant tumors is of great significance. This article concluded the research about the progression of nutrition research, reviewed the status of clinical nutrition research of tumor patients and indicated a new idea about tumor treatment and nutritional research. In occurence and development of tumor, using appropriate nutritional screening tools such as nutritional risk screening and subjective global assessment for patients with comprehensive nutritional screening and evaluation as soon as possible, reasonable and effective nutritional therapy has positive clinical value to patients, which will upgrade the quality of life and improve the prognosis.