This article describes the successful application of the transtheoretical model on diet control and medicine in-take behavioral modification for an elderly hemodialysis patient; the nursing period was from September 17, 2016 to October 14, 2017. We have collected the data and made a comprehensive nursing assessment through observation, interview and the patient’s medical records. Major issues included poor control of blood phosphorus/ lack of correct awareness and management. Different goals were set for different stages and different strategies including consciousness raising, emotional release, self-reevaluation, environmental reevaluation, social-liberation, assisting relationships, counter-conditioning, reinforced management, stimulus control, self-commitment were utilized to improve the self-efficacy and decision-making trade-off of the patient. These approaches enabled the case to comply with the low-phosphorus diet and the in-take of the anti-phosphate agent. In conclusion, the transtheoretical model can be applied to identify the changes of the patient. By sharing this experience, the author hopes to provide other medical personnel with an example on how the transtheoretical behavioral modification can be used to care forthis type of elderly patient.