As a diffuse lung disease with unknown etiology, the precise pathogenesis of idiopathic pneumonic fibrosis (IPF) remains a controversial issue. Genes associated with the immune system have been demonstrated to play an important role in the development of IPF. As a result, we analyzed single-cell RNA sequencing data from IPF patients and healthy controls and found B cells to be elevated in IPF patients. The additional dataset GSE53845 was used for immunoinfiltration analysis by CIBERSORT,  and based on the results, WGCNA was performed to identify genes closely associated with B cells. Differential analysis of B-cell-associated genes was performed, and the differentially expressed genes were analyzed by GO and KEGG. Enrichment of DEGs for extracellular matrix- and protein digestion- and uptake-related genes was shown, which partially overlapped with the analysis of B-cell markers. The intersection of DEGs and B-cell markers was examined, and a predictive model was constructed with the intersecting genes, which indicated that IGHM expression was significantly associated with IPF. In summary, through bioinformatic analysis of scRNA and mRNA datasets, we propose that functional anomalies in B cells play a significant role in IPF. In addition, IGHM holds the potential to serve as a therapeutic target.