Background <p>Aortic dissection (AD) is a critical macrovascular emergency related to the morphology of vascular smooth muscle cell (VSMC). LncRNA SNHG1 is abnormally expressed in AD patients, but its specific mechanism and prognostic value remain unclear. This study investigated lncRNA SNHG1 expression, diagnostic and prognostic value in AD.</p> Methods <p>RT-qPCR detected lncRNA SNHG1 expression in AD patients. ROC evaluated diagnostic value. Kaplan-Meier curve and Cox Proportional Hazards Regression Model analyzed prognostic value. Cell counting kit 8 (CCK-8) determined cell activity, flow cytometry measured apoptosis, and luciferase reporter gene analysis identified lncRNA SNHG1-miR-16-5p targeting.</p> Results <p>LncRNA SNHG1 expression in AD patients was clearly lower than that in controls (<i>P</i> &lt; 0.001), and negatively correlated with AD risk score. LncRNA SNHG1 exhibited diagnostic and prognostic value in AD. In vitro, overexpression of lncRNA SNHG1 promoted VSMCs proliferation and inhibited apoptosis. Luciferase reporter genes showed that lncRNA SNHG1 directly targeted miR-16-5p, with negative correlation. Up-regulation of miR-16-5p reversed the pro-proliferative and anti-apoptotic effects of lncRNA SNHG1.</p> Conclusions <p>LncRNA SNHG1 may participate in the pathogenesis of AD by targeting miR-16-5p and become a potential diagnostic biomarker for AD.</p>