A new series of paeonol derivatives containing the 1,4-benzoxazinone and 1,2,3-triazole moieties were synthesized and evaluated for their cytotoxicity in vitro against human non-small cell lung cancer NCI-H1299 cells and human cervical carcinoma HeLa cells. Among them, compared with that of paeonol, compounds 8-acetyl-4-{[(1-(5-chloro-2-nitrophenyl)-1 H-1,2,3-triazol-4-yl]methyl}-5-methoxy-2 H-1,4-benzoxazin-3(4 H)-one, 8-acetyl-4-[(1-mesityl-1 H-1,2,3-triazol-4-yl)methyl]-5-methoxy-2 H-1,4-benzoxazin-3(4 H)-one, and 8-acetyl-5-methoxy-4-{[(1-(naphthalen-1-yl)-1 H-1,2,3-triazol-4-yl]methyl}-2 H-1,4-benzoxazin-3(4 H)-one exhibited significant inhibitory activity toward the human non-small cell lung cancer NCI-H1299 cells (IC50 = 13.36 ± 0.003, 19.75 ± 0.3, 15.79 ± 0.05 μg mL−1). The last compound also exhibited significant inhibitory activity toward the human cervical carcinoma HeLa cells (IC50 = 19.73 ± 1.0 μg mL−1).