Background:Chronic atrophic gastritis (CAG) is an established pre-cancerous lesion of intestinal type gastric cancer(GC),H pylori infection is the main pathogenic cause,this study intends to study the pathogenesis of atrophic gastritis(Hp+) from the lncRNA-miRNA-mRNA ceRNA regulatory network, in order to provide the oretical basis and data support for the treatment of atrophic gastritis.Results:GSE111762 downloaded from GEO database was used to analyze the differentially expressed lncRNAs and mRNAs(DEGs).A total of 395 differentially expressed lncRNA (225 upregulated,170 downregulated) and 1093 DEGs ( 674 upregulated, 419 downregulated) are obtained. Through the cross-mapping of miRcode, starBase, Sponescan,miRTarBase and miRBase databases,16 miRNAs were predicted,and the lncRNA-miRNA-mRNA ceRNA regulatory network consisting of 71 IncRNAs,16 miRNAs and 597 mRNAs was constructed.597 DEGs were analyzed by David database for functional enrichment. A total of 250 GO enrichment items were obtained, including 160 BP entries, 48 CC entries and 42 MF entries,29 signal pathways were obtained by enrichment analysis of KEGG pathways, mainly p53 signaling pathway, PI3K-Akt signaling pathway and MAPK signaling pathway. Using Cytoscape plug-in CytoHubba to filter 597 DEGs with "MCC, MNC, Degree" top20 as screening conditions, Eleven key hub targets are obtained from the intersection of jvenn.Protein interaction analysis of key hub targets through Cytoscape plug-in GeneMania, it was found that 87.65% displayed similar co-expression characteristics.Construct ceRNA regulatory network of the key hub targets,11 mRNAs(such as BRCA1, RAD54L),12 miRNAs(such as hsa-miR-340-5p,hsa-miR-182-5p) and 58 lncRNAs(such as PCGEM1,FTX) were predicted. Conclusions:Clarify the complex reticular regulation of atrophicgastritis with multi-targets, multi-pathways and multi-pathways.Which provides a new idea for the study of the mechanism of action of atrophicgastritis (Hp+) and a potential target for its treatment,thus to further early diagnosis and reversal of gastric cancer.