Thirty-three 1,3-dihydro-2H-indolin-2-one derivatives bearing α, β-unsaturated ketones were designed and synthesized via the Knoevenagel condensation reaction. The cytotoxicity, in vitro anti-inflammatory ability, and in vitro COX-2 inhibitory activity of all the compounds were evaluated. Compounds4a,4e,4i-4j,and 9dexhibited weak cytotoxicity and different degrees of inhibition against NO production in LPS-stimulated RAW 264.7 cells. The IC50values of compounds4a,4i, and4jwere 17.81 ± 1.86 μM, 20.41 ± 1.61 μM, and 16.31 ± 0.35 μM, respectively. Compounds4eand9dshowed better anti-inflammatory activity with IC50values of 13.51 ± 0.48 μM and 10.03 ± 0.27 μM, respectively, which were lower than those of the positive control ammonium pyrrolidinedithiocarbamate (PDTC). Compounds4e,9h, and9ishowed good COX-2 inhibitory activities with IC50values of 2.35 ± 0.04 µM, 2.422 ± 0.10 µM and 3.34 ± 0.05 µM, respectively. Moreover, the possible mechanism by which COX-2 recognized4e,9h, and9iwas predicted by molecular docking. The results of this research suggested that compounds4e,9h, and9imight be new anti-inflammatory lead compounds for further optimization and evaluation.