Background?Chronic obstructive pulmonary disease (COPD) is a severe public health problem. Cigarette smoke (CS) is a risk factor for COPD and lung cancer. The underlying molecular mechanisms of CS-induced malignant transformation of bronchial epithelial cells remain unclear. In this study, we describe a lung-on-a-chip to explore the possible mechanistic link between cigarette smoke extract (CSE)-associated COPD and lung cancer.Methods?An in vitro lung-on-a-chip model was used to simulate pulmonary epithelial cells and vascular endothelial cells with CSE. The levels of IL-6 and TNF-α were tested as indicators of inflammation using an enzyme-linked immune sorbent assay. Apical junction complex mRNA expression was detected with qRT-PCR as the index of epithelial-to-mesenchymal transition (EMT). The effects of CSE on the phosphorylation of signal transduction and transcriptional activator 3 (STAT3) were detected by West blotting. Flow cytometry was performed to investigate the effects of this proto-oncogene on cell cycle distribution. Results?Inflammation caused by CSE was achieved in a lung-on-a-chip model with a mimetic movement. CSE exposure induced the degradation of intercellular connections and triggered the EMT process. CSE exposure also activated the phos-phorylation of proto-oncogene STAT3, while these effects were inhibited with HJC0152. Conclusions?CSE exposure in the lung-on-a-chip model caused activation of STAT3 in epithelial cells and endothelial cells. HJC0152, an inhibitor of activated STAT3, could be a potential treatment for CS-associated COPD and lung cancer.