Cancer is the leading cause of morbidity and mortality, and about one in six people die from cancer globally. Approximately 20% to 70% of cancer patients are accompanied with malnutrition, and nutrition support plays an important role among cancer patients. However, the utilization of nutrition support is generally irrational in clinical practices and it is affected by multiple factors. Logic models not only present a framework to improve intervention of health care setting but also identify all the elements, pathways, outcomes, and their relationships between systems. This study developed a logic model of nutrition support for cancer patients based on current literature and conducted interview with medical staff in Macao to validate the logic model. In addition, suggestions were given as references to improve the utilization of nutrition support among cancer patients.