The invention provides a coumarin glycoside compound, and a preparation method and application thereof. The preparation method comprises the steps of using ethyl alcohol for carrying out reflux extraction and concentration on acalypha australis to obtain a thick paste; then adding water for dissolving, and sequentially using a petroleum ether, ethyl acetate and n-butyl alcohol for extracting to obtain an n-butyl alcohol extract; loading the n-butyl alcohol extract to a large pore resin absorption column, adopting the ethyl alcohol as a moving phase for carrying out gradient elute, removing a solvent of a flow part of the moving phase which is the ethyl alcohol with the volume concentration being 30 percent, and obtaining sub-fraction C; loading the sub-fraction C to a silicagel column, adopting a chloroform-methyl alcohol-water system as a moving phase for carrying out gradient elute, and removing a solvent of a flow part of the moving phase which is the chloroform-methyl alcohol-water system with the volume ratio being 5:1:0.5, and obtaining fraction C-2; finally sequentially loading the fraction C-2 on a sephadex column and a gel resin column, using methyl alcohol as a moving phase for carrying out elution, and removing a solvent to obtain the compound. The coumarin glycoside compound has remarkable liver protection activity, and can be applied to preparation of a liver-protection medicine.