Abstract: The syntheses and screening for five series of new flavonoid compounds with 3'-or 4'-substituted methyl gronp are reported. Among these compounds, the anti-early-pregnancy activity of I₄ in mice has been noticed to be comparable with that of the active principle of Plumbago zeylanica, 2-methyl-5-hydroxy-1,4-naphthoquinone. Compounds Ⅳ and V₃ resemble in strncture apigenin, and recordil (a remedy for coronary insufficiency) respectively. Their structure-activity relationships are under investigation.