Effects of quercetin 3-$eta$-D-glucoside, resveratrol, and curcumin on A549 lung cancer cell proliferation and the mechanism of these phytochemicals in regulating apoptosis and cell cycle arrest were investigated. A549 cells were treated with quercetin 3-$eta$-D-glucoside, resveratrol, or curcumin at $37^{circ}C$ for 96 hr and cell viability was measured with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Proteins related to apoptosis and cell cycle in A549 cells were quantified with Western blotting assay. Quercetin 3-$eta$-D-glucoside, resveratrol, and curcumin inhibited A549 cell proliferation in a dose-dependent manner (p<0.05). Quercetin 3-$eta$-D-glucoside significantly decrease the expression level of CDK4 at concentrations of 5 mM and above (p<0.05). Curcumin lowered expression level of Bcl-2, CDK4, and cyclin D1 at concentrations of 100, 50, and above, and 50 mM and above, respectively (p<0.05). These results suggest that phytochemicals, which can be found in a normal diet, inhibit lung cancer cell proliferation and regulate the expression of the proteins involved in apoptosis and cell cycle.