The invention discloses a preparation method of bicuculline and fumarine. The preparation method comprises the following steps: 1) extracting: pulverizing a medicinal material, extracting with an acidmethanol or ethyl
alcohol solution to obtain an extracting solution A, and conducting vacuum concentration to obtain a concentrated solution B; 2) separating and enriching: taking the concentrated solution B, regulating the PH, adsorbing through an inverse
polymerization filler C, eluting with water firstly to obtain a washing solution D, then desorbing with an alcoholic solution E, collecting adesorbed solution F, and desorbing with an alcoholic
solution G to obtain a desorbed solution H; 3) purifying: taking the desorbed solution H, conducting vacuum concentration to regulate the PH, standing, filtering a precipitate, stirring and mixing the precipitate, obtaining a solution J through
silica gel chromatograph; conducting vacuum concentration on the desorbed solution F, regulating the PH to 9-10, and separating out a precipitate K; and regulating the PH of the washing solution D to 9-10, and separating out a precipitate L; and 4) crystalizing and
drying: conducting vacuum concentration on the solution J, crystalizing and
drying the solution J to obtain a pure product of bicuculline; and crystalizing and
drying the precipitate K and the precipitate L to obtain a pure product of fumarine. By using the method, the yield is high, the purity is high, and the method can be applied to industrial production.