Objective To explore the effect of nursing intervention guided by Motivational Interviewing (MI) on scar improvement in patients undergoing keloid scar excision. Methods A total of 86 patients who underwent keloid scar excision in Jinan Hospital of Integrated Traditional Chinese and Western Medicine from January 2021 to January 2024 were selected, and they were divided into the control group and the observation group by the random number table method, with 43 patients in each group. The control group received conventional nursing intervention, and the observation group received nursing intervention guided by MI. The post-traumatic stress disorder severity, scar status, recovery time indicators and psychological state were compared between the two groups. Results The PLC-C score of the observation group after intervention was lower than that of the control group (P <0.05). The VSS score of the observation group after intervention was lower than that of the control group (P <0.05). The wound healing time, postoperative suture removal time and redness and swelling regression time of the observation group were shorter than those of the control group (P <0.05). The scores of SAS and SDS in the observation group after intervention were lower than those in the control group (P <0.05). Conclusion Nursing intervention guided by MI has a good effect on patients undergoing keloid scar excision. It can effectively reduce the severity of post-traumatic stress disorder, improve negative emotions, promote wound healing and regression of redness and swelling, and enhance scar improvement effect.