The invention discloses a hexacyclic alkaloid compound, a preparation method and an application thereof. The hexacyclic alkaloid compound is obtained through fermentation, extract extraction, chromatography and purification on a Penicilliumramigena (YNCA0361) strain, a molecular formula is C19H20N2O6, a structural formula is shown as the following, the compound is named as Penicilliumramigena A; a bacterial strain preservation number of the Penicilliumramigena (YNCA0361) strain is CGMCC No.4824, and the preservation date is 2nd, May, 2011. The preparation method comprises the steps of solid fermentation, extract extraction, slica column chromatography, and separation and purification by high pressure liquid chromatography. The application of the present invention is the application of the hexacyclic alkaloid compound for preparing tobacco mosaic virus medicines. The compound has good application prospect for preparing the tobacco mosaic virus medicines. The compound has good activity, and can be obtained through a biological fermentation approach, and can be used as the guiding compound for the tobacco mosaic virus medicines.