A terrestrial plant fruit extract was adopted to prevent hydrate accumulation. Four groups with different polarities, water-soluble, n-butanol-soluble, ethyl acetate-soluble, and petroleum ether-soluble portions, were obtained by prefractionation of the plant-extract hydrate antiagglomerant (AA). The hydrate antiagglomeration effect was tested in a high pressure transparent sapphire cell, and the active components were found mainly in the ethyl acetate-soluble portion that accounts for approximately 4.0% of the whole plant extract. Through further separation and purification, the five kinds of components obtained proved experimentally to have the effect of preventing hydrate agglomeration. Their molecules and structural formulas were inferred by the high resolution mass spectrum and nuclear magnetic resonance analysis. Compared with the spectrum library, the components were determined to be eriodictyol, apigenin, naringenin, luteolin, and 5-(4-hydroxy-6,7-dimethoxy-3-methylchroman-2-yl) benzene-1,2,3-triol. The tests on the extracted components and the commercial products verified their effect of preventing hydrate agglomeration, where apigenin and luteolin performed better than others.