〔Abstract〕 Objective To investigate the effects and underlying mechanisms of high mobility group nucleosome-binding domain protein 2(HMGN2) on lung adenocarcinoma cells. Methods This work first analyzed the association between HMGN2 and lung adenocarcinoma tissues using The Cancer Genome Atlas(TCGA) database. Lung adenocarcinoma tissues and adjacent normal tissues were collected to compare the differential expression levels of HMGN2. The expression of HMGN2 mRNA in lung adenocarcinoma cell lines A549 and NC-H1299 were detected by qRT-PCR and Western blot. HMGN2 expression was knocked down using si-RNA technology, with the control group transfected with an equivalent amount of NC-siRNA, and the si-RNA group transfected with si-HMGN2. Stable transfected cell lines were established based on si-RNA knockdown efficiency. The effects of HMGN2 knockdown on the growth, movement, and spread of lung adenocarcinoma cells were assessed using CCK-8, Transwell assays, scratch assays, colony formation assays, and EdU assays. Transcriptome sequencing analysis revealed pathways related to tumorigenesis associated with HMGN2. The relative expression levels of MAPK pathway proteins after HMGN2 knockdown were detected by Western blot. Results HMGN2 mRNA expression was significantly elevated in lung cancer tissues and lung adenocarcinoma cell lines(P<0.05). After HMGN2 knockdown, cell proliferation, migration, and invasion were significantly reduced(P<0.05), and the phosphorylation levels of the MAPK signaling pathway markedly decreased(P<0.05). Conclusion HMGN2 enhances the proliferation, migration, and invasion of lung adenocarcinoma cells, and its mechanism may be closely related to the activation of the MAPK signaling pathwayviaphosphorylation.