Abstract: Objective 　To observe the inhibitive effect of aspirin on the proliferation of lung adenocarcinoma cell line A549 in vitro. Methods 　MTT assay was used to observe the antiproliferative effects of aspirin, combined with oxaliplation on A549 cells ; Flow cytometry was used to analyze the effects of aspirin on the dist ribution of A549 cells cycle, HE and the TdT-mediated d-UTP nick end-labeling assay (TUNEL) technique were used to observe the effect s of aspirin on the apoptosis of A549 cells. Results 　Aspirin inhibited the proliferation of A549 cells in a dose-dependent manner. After treatment, the cell percent of G₀/G₁ phase increased, and that of S and G₂/ M phase decreased, A I increased from 3. 67 % ±1. 15 % to 26. 33 % ±2. 52 % with the raise of aspirin concent ration. A549 cells exhibited typical morphologic features of apoptosis by light microscopy. When aspirin (2. 5mmol/ L) and oxaliplation ( ≥6. 25 ug/mL) were combined, the inhibitory effect was enhanced in a symergistic or additive pattern. Conclusion 　Aspirin can inhibit the proliferation of lung adenocarcinoma cells A549 through influencing the dist ribution of cell cycle and inducing apoptosis of A549 cells. Aspirin combined with oxaliplation shows significantly synergistic anti2tumor effect s on A549 cells.