The crystal structure of the title compound (E)-N-(4-fluorobenzylidene)-3-(methylthio)-5-(3,4,5-trimethoxyphenyl)-4H-1,2,4-triazol-4-amine (C19H19FN4O3S, M-r = 402.44) was synthesized, and its structure was characterized by H-1-NMR, C-13-NMR, ESI-MS and single-crystal X-ray diffraction. The crystal belongs to the triclinic system, space group P (1) over bar with a = 9.228(13), b = 10.364(14), c = 10.641(14) angstrom, alpha = 85.323(3), beta = 75.172(2), gamma = 80.903(3)degrees, mu = 0.20 mm(-1), M-r = 402.44, V = 970.64(10) angstrom(3), Z = 2, D-c = 1.377 g/cm(3), F(000) = 420, R = 0.0484 and wR = 0.1474 for 3181 observed reflections with I > 2 sigma(I). In addition, the preliminary bioassay indicated that the title compound 5 exhibits better inhibitory activity against Hela than 5-fluorouracil.