〔Abstract〕 Objective To explore the expression levels of long non-coding RNA (lncRNA) H19 and microRNA-22-3p (miR-22-3p) in the serum of patients with acute myocardial infarction (AMI) and their diagnostic value for AMI. Methods A total of 176 AMI patients from the Department of Cardiology were selected as the experimental group and were divided into ST-segment elevation myocardial infarction (STEMI) group and non-ST-segment elevation myocardial infarction (NSTEMI) group based on their medical history and electrocardiogram. Meanwhile,156 patients with negative angiography during the same period were selected as the control group (CON group). The relative expression levels of lncRNA H19 and miR-22-3p in the serum of the two groups were detected by real-time fluorescence quantitative polymerase chain reaction. The diagnostic value of miR-22-3p and lncRNA H19 in AMI was evaluated by receiver operating characteristic curve (ROC) analysis. The levels of serum cardiac troponin I (cTnI), creatine kinase (CK), creatine kinase MB isoenzyme (CK-MB), and high-sensitivity C-reactive protein (CRP) were detected in all study subjects. Spearman correlation analyses were used to evaluate the correlations between lncRNA H19 and miR-22-3p and cTnI, CK, CK-MB and CRP. Results Compared with the control group, the expression level of lncRNA H19 was upregulated and the expression level of miR-22-3p was downregulated in the AMI group (all P < 0.05); compared with the NSTEMI group, the expression level of lncRNA H19 was upregulated and the expression level of miR-22-3p was downregulated in the STEMI group (P < 0.05). The areas under the ROC curves (AUC) for the diagnosis of AMI by miR-22-3p, lncRNA H19 and their combination were 0.555, 0.977, and 0.983, respectively. lncRNA H19 was positively correlated with cTnI, CK,CK-MB and CRP (P < 0.05), and negatively correlated with LVEF (P < 0.05); miR-22-3p was negatively correlated with cTnI, CK and CRP, and positively correlated with LVEF (P < 0.05).Conclusion The expression level of lncRNA H19 is elevated and the expression level of miR-22-3p decreased in AMI patients, and their levels may have potential value as an auxiliary biomarker for AMI diagnosis and cardiac function assessment.