The invention discloses an amorphous levo-praziquantel solid and a preparation method thereof. The solid has no characteristic absorption peaks in a powder X-ray diffraction pattern. The preparation method of the amorphous levo-praziquantel solid includes a step (a) and a step (b) as follows: (a) dissolving levo-praziquantel crystal form powder and/ or oily levo-praziquantel in a mixed solvent ofa first organic solvent or a second organic solvent and water, and then placing the mixture at 50 DEG C to 100 DEG C for volatilization; and (b) dissolving levo-praziquantel crystal form powder and/ or oily levo-praziquantel in a third organic solvent, and then adding a high molecular polymer to induct precipitation of the solid. The method combines multiple clinical advantages of the levo-praziquantel and the advantages that the reactivity of an amorphous structure is generally greater than that of the same substance, and paves the way for the listing of the amorphous levo-praziquantel solidand/ or medicine which contains the amorphous levo-praziquantel solid as an active ingredient and treats schistosomiasis and a plurality of parasitic diseases.