Objective: To investigate the application effects of armor chest straps in patients with sternal dehiscence after repair surgery. Methods: This study was a retrospective cohort study. The 11 patients who were admitted to the First Affiliated Hospital of Air Force Medical University (hereinafter referred to as the hospital) from March 2020 to March 2021 and used conventional chest straps after sternal dehiscence repair surgery were included in conventional chest strap group. The 12 patients who were admitted to the hospital from April 2021 to March 2022 and used armor chest straps after sternal dehiscence repair surgery were included in armor chest strap group. A special team for sternal dehiscence repair was set up, and the nurses in charge in the team instructed the patients in 2 groups on the correct abdominal breathing method, and the members of the surgical team performed the personalized surgery and wore the corresponding chest straps for the patients in 2 groups. The abdominal breathing frequency and chest breathing frequency on the first day after surgery were recorded. The pain intensity at 6, 24, 48, and 72 h after surgery was self-rated by the patients using numerical rating scale. The time of the first active cough and the time of wound healing after surgery were recorded. At postoperative suture removal, the cutting length of sutures induced by respiratory exercise was recorded. Whether there were complications such as redness, swelling, and exudation in flaps within 2 weeks after surgery were recorded, whether there were complications such as wound dehiscence or infection during follow-up of 3-12 months were recorded, and the incidence proportion of postoperative complications was calculated. At 6 months after surgery, the patients' scar status was evaluated by the Vancouver scar scale. Results: The abdominal breathing frequency of patients in armor chest strap group was (16.3±1.2) times/min on the first day after surgery, which was significantly higher than (5.3±1.4) times/min in conventional chest strap group (t=20.00, P<0.05), and the chest breath-ing frequency was (1.2±0.8) times/min, which was significantly lower than (12.4±1.5) times/min in conventional chest strap group (t=22.36, P<0.05). The pain intensity scores of patients in armor chest strap group at 6, 24, 48, and 72 h after surgery were significantly lower than those in conventional chest strap group (with t values of 15.07, 14.70, 13.66, and 11.03, respectively, P<0.05). The time of the first active cough and the time of wound healing after surgery of patients in armor chest strap group were significantly sooner than those in conventional chest strap group (with t values of 5.51 and 8.90, respectively, P<0.05). At postoperative suture removal, the cutting length of sutures induced by respiratory exercise of patients in conventional chest strap group was 2.0 (0, 5.0) mm, which was significantly longer than 2.0 (1.0, 2.0) mm in armor chest strap group (Z=4.10, P<0.05). There was no statistically significant difference in the incidence proportion of postoperative complications of patients between the 2 groups (P>0.05). At 6 months after surgery, the scar score of patients in armor chest strap group was 4.1±1.4, which was significantly lower than 5.6±1.4 in conventional chest strap group (t=2.71, P<0.05). Conclusions: The application of armor chest strap in patients with sternal dehiscence after repair surgery can increase the abdominal breathing frequency, reduce the wound cutting force, effectively relieve postoperative pain, increase the first active cough and wound healing speed, and alleviate postoperative scar proliferation, achieving good application effect.