Abstract: Objective: To investigate the correlation between serum long non-coding RNA small nucleolar RNA host gene 1(lncRNA SNHG1)and in-stent restenosis(ISR)in patients with acute ST-segment elevation myocardial infarction (STEMI).Methods: 150 patients with STEMIwho received selective percutaneous coronary intervention(PCI)in the cardiovascular department of our hospital from January 2020 to May 2021 were selected.According to whether ISR occurred or not, the patients were divided into ISR group (28 cases) and non-ISR group(114 cases), with 8 cases lost to follow-up.The level of serum lncRNA SNHG1 was measured by real-time fluorescence quantitative polymerase chain reaction (RT-qPCR) and the clinical data of patients were collected.Results: Compared with non-ISR group, the smoking rate, diabetes rate, TC level, LDLC level and TBIL level inISR group significantly increased (P＜0.05), and the level of serum lncRNA SNHG1 relative expression significantly decreased (P＜0.05).ROC curve results showed that serum lncRNA SNHG1 predicted intrastent restenosis in STEMIpatients with a critical value of 0.95, AUC of 0.863 (95% CI:0.764-0.962), sensitivity of 70.18%, and specificity of 89.29%.The incidence of ISR in patients with lncRNA SNHG1 low level was higher than that in patients with lncRNA SNHG1 high level (P＜0.05), and the mean time without restenosis was shorter (P＜0.05).Conclusion: Serum lncRNA SNHG1 has a certain predictive value for ISR, and low lncRNA SNHG1 level is a risk factor of ISR after PCIin patients with STEMI.