A method for synthesizing an important intermediate condensation compound of formula II of Voriconazole or an acid addition salt thereof, comprising reacting a compound of formula III with a compound of formula IV in an aprotic organic solvent at a certain reaction temperature, in the presence of zinc and a Lewis acid, with or without an activator, as shown in a reaction scheme 1, wherein the method comprises following steps: (a1) mixing the compound of formula III, zinc and the Lewis acid with the aprotic organic solvent to form a suspension; (b1) mixing the compound of formula IV with the aprotic organic solvent, optionally in the presence of the activator, to form a solution; (c1) adding slowly the solution formed in step (b1) into the suspension formed in step (a1) and reacting to provide the intermediate condensation compound of formula II; and (d1) optionally converting the intermediate condensation compound of formula II to an acid addition salt thereof; or, (a2) mixing the compound of formula III, zinc and the Lewis acid with the aprotic organic solvent to form a suspension; (b2) mixing the compound of formula IV with the aprotic organic solvent to form a solution; (c2) adding slowly the solution formed in step (b2) into the suspension formed in step (a2), optionally in the presence of the activator and reacting to provide the intermediate condensation compound of formula II; and (d2) optionally converting the intermediate condensation compound of formula II to an acid addition salt thereof; or, (a3) mixing the compound of formula III, the compound of formula IV, and the Lewis acid with the aprotic organic solvent to form a suspension; (b3) adding zinc into the suspension, optionally in the presence of the activator, to provide the intermediate condensation compound of formula II; and (c3) optionally converting the intermediate condensation compound of formula II to an acid addition salt thereof; (a1) mixing the compound of formula III, zinc and the Lewis acid with the aprotic organic solvent to form a suspension; (b1) mixing the compound of formula IV with the aprotic organic solvent, optionally in the presence of the activator, to form a solution; (c1) adding slowly the solution formed in step (b1) into the suspension formed in step (a1) and reacting to provide the intermediate condensation compound of formula II; and (d1) optionally converting the intermediate condensation compound of formula II to an acid addition salt thereof; or, (a2) mixing the compound of formula III, zinc and the Lewis acid with the aprotic organic solvent to form a suspension; (b2) mixing the compound of formula IV with the aprotic organic solvent to form a solution; (c2) adding slowly the solution formed in step (b2) into the suspension formed in step (a2), optionally in the presence of the activator and reacting to provide the intermediate condensation compound of formula II; and (d2) optionally converting the intermediate condensation compound of formula II to an acid addition salt thereof; or, (a3) mixing the compound of formula III, the compound of formula IV, and the Lewis acid with the aprotic organic solvent to form a suspension; (b3) adding zinc into the suspension, optionally in the presence of the activator, to provide the intermediate condensation compound of formula II; and (c3) optionally converting the intermediate condensation compound of formula II to an acid addition salt thereof; <EOS>