Abstract: Nineteen kinds of 2-(E)-benzylidene-5-(N-substituted aminomethyl) cyclopentanones were synthesized via Mannich reaction or amine exchange reaction and identified spectrometrically. One compound exhibited significant antiinflammatory activity, showing obvious inhibitory effect on xyleneinduced mice ear swelling, carrageenininduced rats paw edema and increased capillary permeability induced with acetic acid in mice. Its ED₅₀ values in these inflammatory models were calculated to be 67.8 mg·kg^-1, 25.3 mg·kg^-1 and 41.8 mg·kg^-1 respectively, nearly equal to those of ibuprofen and aspirin.