Objective To investigate the influencing factors of inter-arm systolic blood pressure difference (IASBPD) in the elderly inpatients. Methods A total of 1 542 patients admitted in our department from January 2016 to June 2017 were recruited in this study. In 24 h after being in stable or relatively stable condition, these patients underwent non-invasive blood pressure test. According to their IASBPD values, they were assigned into 0-5 mmHg group (n=570), 6-15 mmHg group (n=834), and ≥16 mmHg group (n=138). Their body mass index (BMI), other complications and C-reactive protein (CRP) were collected and compared among the 3 groups. Logistic regression analyses were applied to explore the related factors affecting IASBPD.Results The total IASBPD value was (8.5±5.4)mmHg, and the value was (10.6±5.2)mmHg and (4.3±2.6)mmHg respectively between the patients with and without hypertension (P＜0.001). Both univariate analysis of variance and univariate logistic regression analysis showed that female, BMI, CRP level, hypertension, family history of hypertension, use of hypotensive drugs, diabetes, hyperlipidemia and other complications were related factors infecting IASBPD (P<0.05). Multivariate logistic regression analysis revealed that female (OR=2.286,5%CI 1.784-2.929), BMI (OR=1.101, 95%CI 1.054-1.150), hypertension (OR=7.726, 95%CI 5.575-10.706), diabetes (OR=1.701, 95%CI 1.125-2.570), hyperlipidemia (OR=2.182, 95%CI 1.660-2.869) and CRP level (OR=1.260,5%CI 1.190-1.333) were independent risk factors for IASBPD. Conclusion IASBPD is quite larger in the elderly inpatients. Female, BMI, diabetes, hypertension, hyperlipidemia and CRP level are independent risk factors for IASBPD.