A pharmaceutical mixture for the treatment of hepatitis and its preparation method are disclosed. The method includes the following steps: pulverize the plants, macerate and extract the plant with water, concentrate the aqueous extract as the first concentrate; add ethanol to form a precipitate, collect and concentrate the liquid phase to form the second concentrate, and dry it; pass the second concentrate through the resin, elute with water, water-ethanol mixture and ethanol, collect and concentrate the water-ethanol and ethanol elution fraction as the third concentrate, and dry it. The plants in the present invention are Boehmeria frutescens Thunberg, Boehmeria nivea or the nettle family.