Lung adenocarcinoma (LUAD), a prevalent form of non-small cell lung cancer (NSCLC), has a high incidence and mortality rate. However, its molecular regulatory mechanisms have yet to be fully understood. The purpose of this study was to look into how NADPH quinone oxidoreductase-1 (NQO1) and it miR-485-5p and affected LUAD cells. The levels of miR-485-5p and NQO1 expression in LUAD cells and tissues were determined by means of quantitative reverse transcription polymerase chain reaction. The viability, proliferation, migration, and apoptosis of LUAD cells were assessed using cell counting Kit-8, 5-bromo-2'-deoxyuridine, transwell, and caspase-3 assays, respectively. Western blot experiments were used to examine the relative protein expression of matrix metallopeptidase 2 and matrix metallopeptidase 9, as well as the phosphorylation of phosphoinositide 3-kinase (PI3K) and protein kinase B (Akt) in LUAD cells. Luciferase and RNA pull-down experiments were also conducted for the verification of miR-485-5p's underlying relationship with NQO1. In our study, we found that LUAD cells and tissues had miR-485-5p downregulation and NQO1 upregulation. The experimental outcomes indicated that miR-485-5p overexpression in LUAD cells reduced their malignant behaviors, suppressed PI3K and Akt phosphorylation, and facilitated apoptosis. The results also revealed that NQO1 was a direct miR-485-5p target, and that NQO1 could reverse miR-485-5p's inhibitory effect on the malignant phenotype of LUAD cells. Furthermore, it was also observed that through targeting NQO1, miR-485-5p could suppress LUAD cell migration and proliferation, further blocking the phosphorylation of PI3K and Akt and inducing apoptosis among LUAD cells. In conclusion, the miR-485-5/NQO1 axis regulates LUAD progression through the PI3K/Akt pathway.