【Abstract】 Objective To explore the values of SMART nursing principles in preventing the occurrence of delayed hematoma after coronary angiography in elderly patients. Methods From August 2013 to January 2017, 120 patients with acute coronary syndrome in our hospital were selected as the research objects. All the patients were divided into observation group(60 cases) and control group(60 cases), accordeding to the random lottery envelopes randomly. All the patients were treated by transradial approach coronary intervention. The control group was given the perioperative routine care. The observation group was given the SMART nursing principles intervention based on the control group. The nursing of two groups was observed for 1 month. Results The incidence of Delayed Limb hematoma in the observation group and the control group were 17% and 133%, respectively. The observation group was significantly lower than that of the control group (P＜005). The observation group after the nursing of prescribed medication, self monitoring, motion management and diet management score were 1235±209, 2184±283, 1152±198 and 1543±237, while the control group scores were 974±179, 1749±221, 824±174 and 1321±214 (P＜005). The satisfaction degree of the observation group and the control group was 100% and 883%, respectively. The satisfaction of the observation group was significantly higher than that of the control group (P＜005). The pain scores in the observation group and control group after nursing were 212±038 point and 272±045 point, which were significantly lower than those before treatment (P＜005), The pain scores of observation group were significantly lower than that of the control group (P＜005). Conclusion The SMART nursing principles can prevent the occurrence of delayed postoperative limb hematoma after transradial coronary angiography in elderly patients, improve selfcare ability, relieve pain and improve nurse patient relationship.