The invention discloses a preparation method for atropine sulfate. The preparation method comprises the following steps: 1) adding dry powder of daturae flower into hydrochloric acid with a concentration of 1 to 4% and a volume 0.5 to 1 time of the volume of the dry powder for wetting and swelling, then adding the swollen daturae flower powder into a percolating barrel, adding the hydrochloric acid with a concentration of 1 to 4%, dipping the powder for 24 h or above and carrying out percolating so as to obtain brown-yellow stiff paste; 2) dissolving brown-yellow stiff paste in acetone, adding active carbon, carrying out decoloring and filtering, adding acid drop by drop until a pH value is less than 7 and carrying out standing at room temperature so as to obtain hyoscyamine sulfate; and 3) spreading hyoscyamine sulfate on a sample disc, putting the sample disc into a baking oven, carrying out heating for racemization, then carrying out cooling to obtain a crude atropine sulfate product, adding ethanol, carrying out dissolving under stirring and then filtering, subjecting a filtrate to crystallization overnight and then successively carrying out pressure-reduced filtering and vacuum drying so as to obtain atropine sulfate. According to the invention, the daturae flower is used as a raw material; acid water is used for percolation and extraction; total alkali is obtained through chloroform extraction; sulfuric acid is added into an acetone solution for salt forming so as to obtain hyoscyamine sulfate, then heating is carried out for racemization, and ethanol recrystallization is carried out to obtain atropine sulfate; and the method is simple in process operation, small in pollution, low in cost and suitable for industrial production.