Introduction: Abnormal inter arm systolic blood pressure, inter leg systolic blood pressure and ankle brachial index (ABI) are related to vascular diseases. Our aim was to evaluate the correlation of inter arm systolic blood pressure difference (IASBPD), inter leg systolic blood pressure difference (ILSBPD), and ABI with acute aortic dissection (AAD) and their role in predicting AAD. Methods: In this prospective case-control study, 180 patients with AAD admitted to the emergency department were prospectively and consecutively collected in Tongji Hospital from October 2019 to December 2020. 180 healthy people matched by sex, age and BMI served as control group. All participants were adults over 18 years of age who underwent four-limb blood pressure measurements. IASBPD, ILSBPD and ABI were compared between the two groups and their associations with AAD were analyzed. Results: A total of 360 patients (180 cases and 180 controls) were analyzed. In case group IASBPD was larger [(15.23 \pm 16.15) mm Hg vs. (4.19 \pm 3.63) mm Hg] and ILSBPD was larger (13.00 mm Hg vs. 5.70 mm Hg). ABI was smaller [(0.98 \pm 0.24) vs. (1.12 \pm 0.09)], and the difference was statistically significant (all p 0.05). According to the receiver operating characteristic curve (ROC), IASBPD \ge10 mm Hg (Sen 61.7%, Spe 88.9%), ILSBPD \ge13 mm Hg (Sen 50.6%, Spe 80.6%) and ABI \le0.9 (Sen 53.3%, Spe 87.2%), showed significant correlation with AAD (all p 0.001). Conclusions: Compared with healthy people, IASBPD and ILSBPD levels were higher and ABI levels were lower in patients with AAD. IASBPD \ge10 mm Hg and ILSBPD \ge13 mm Hg can be used as indicators for early screening of AAD, and IASBPD \ge10 mm Hg has better predictive value for the occurrence of AAD. In patients with typical chest pain, attention needs to be paid to measuring blood pressure in the extremities.