Objective: To investigate the relationship between blood pressure variability (BPV) and incidence of post-traumatic stress disorder (PTSD) in trauma patients., Methods: Patients admitted to the department of emergency medicine of the Affiliated Hospital of Xuzhou Medical University for acute trauma from January 2018 to December 2021 were enrolled. The clinical data and blood pressure at admission (T1), 10 minutes before anesthesia (T2), 60 minutes after surgery (T3), and 24 hours after surgery (T4) were collected. Coefficient of variation of blood pressure variation [CV-BP, including coefficient of variation of systolic blood pressure (CV-SBP), coefficient of variation of diastolic blood pressure (CV-DBP), coefficient of variation of mean arterial pressure (CV-MAP)] and its quartile were calculated. Patients were divided into Q1 group (CV-MAP ≤ 7.27), Q2 group (7.27 < CV-MAP ≤ 9.50), Q3 group (9.50 < CV-MAP ≤ 14.05) and Q4 group (CV-MAP > 14.05) according to CV-MAP quartile. The PTSD symptoms of the patients were evaluated using the PTSD scale (PCL-5) one month later, and the patients were divided into the PTSD group and the non-PTSD group according to whether PCL-5 score higher than 38. Then the differences of the above indicators were compared and analyzed. Spearman correlation analysis was used to analyze the relationship between each index and PCL-5 score; the risk factors of PTSD were analyzed by univariate binary Logistic regression. Variables with P < 0.05 were included in the multivariate binary Logistic regression model. The receiver operator characteristic curve (ROC curve) was drawn to analyze the predictive value of CV-MAP on the incidence of PTSD., Results: A total of 112 patients were enrolled, including 24 in PTSD group and 88 in non-PTSD group. Compared with non-PTSD group, the proportion of women, T1 shock index, proportion of intraoperative and postoperative blood transfusion in PTSD group was higher. Besides, PTSD group also had longer PT, more intraoperative and postoperative blood transfusion, and lower postoperative hemoglobin (Hb) level (all P < 0.05). The T1 SBP, DBP, MAP and T4 MAP of patients in PTSD group were significantly lower than those in non-PTSD group [T1 SBP (mmHg, 1 mmHg ≈ 0.133 kPa): 105.0 (86.3, 121.3) vs. 122.0 (112.0, 132.8), T1 DBP (mmHg): 62.5 (50.0, 77.3) vs. 76.0 (68.5, 82.8), T1 MAP (mmHg): 77.8 (60.4, 91.3) vs. 93.3 (82.5, 99.0), T4 MAP (mmHg): 83.8±9.1 vs. 88.7±10.4, all P < 0.05], CV-SBP, CV-DBP and CV-MAP were higher than those in the non-PTSD group [CV-SBP: 12.80 (10.12, 19.16) vs. 9.30 (6.07, 12.95), CV-DBP: 16.62±6.47 vs. 12.40±5.61, CV-MAP: 14.10 (9.25, 18.85) vs. 8.90 (6.93, 13.29), all P < 0.05]. Spearman correlation analysis showed that there was a positive correlation between CV-MAP and PCL-5 scores in patients with acute trauma (r = 0.429, P < 0.001); multivariate binary Logistic regression analysis showed that only CV-MAP [odds ratio (OR) = 1.128, 95% confidence interval (95%CI) was 1.015-1.254, P = 0.025] and CV-DBP (OR = 1.114, 95% confidence interval (95%CI) was 1.016-1.221, P = 0.022) was the risk factor for PTSD in acute trauma patients. Compared with Q1 group, Q4 group was significantly more likely to develop PTSD (OR = 18.6, 95%CI was 1.9-179.1, P = 0.012). CV-SBP, CV-DBP and CV-MAP had certain predictive value on PTSD diagnosis in patients with acute trauma according to ROC curve analysis results [area under the ROC curve (AUC) was 0.713, 0.682 and 0.726, respectively], among which CV-MAP has the highest predictive value. When the cut-off value of CV-MAP was 12.158, the sensitivity was 75.0% and the specificity was 69.3%., Conclusions: Higher BPV after trauma is a risk factor for PTSD. Maintaining stable blood pressure in trauma patients is of great significance for prevention and treatment of PTSD.