The invention discloses a preparation method of a starch-based antibacterial agent for sweet and sour ginger. The preparation method comprises the following steps: after hydrolyzing cellulose acetatewith an oxalic acid solution, adding oxidized starch and collagen, stirring with water, adding chitosan and citric acid and then stirring to obtain the starch-based antibacterial agent for the sweet and sour ginger. The invention discloses the starch-based antibacterial agent for the sweet and sour ginger, and further discloses a preparation method of the sweet and sour ginger with bright color and luster. The preparation method of the sweet and sour ginger comprises the following steps: washing fresh ginger, cutting into ginger pieces, freezing, adding water, heating, adding white sugar and malic acid while stirring, continuously stirring, cooling, standing still and filtering to obtain pretreated ginger; adding mature vinegar and the starch-based antibacterial agent for the sweet and sour ginger into the pretreated ginger, turning and rubbing, sealing, performing sterilization, cooling and carrying out pickling to obtain the sweet and sour ginger with the bright color and luster. Thestarch-based antibacterial agent for the sweet and sour ginger can keep the fresh tender ginger fresh, bright in color and luster, crispy, tasty and refreshing in mouthfeel, sour and sweet and palatable, not boring after being taken for a long time and small in loss of nutritional components.