The invention discloses a corn type mixed feed for a weaned pig and a preparation method thereof. The mixed feed comprises the following raw materials: dried corn, puffed corn, soybean meal, puffed soybean, a wheat germ cake, flour, fish meal, plasma protein powder, whey powder, soya-bean oil, stone flour, calcium hydrogen phosphate, salt, lysine 70%, methionine 99%, threonine 99%, choline chloride 60%, glucose, compound enzyme, a vitamin premix and a trace element premix. The preparation method comprises the following steps: crushing; mixing; and granulation. The invention has the following beneficial effects: nutritional requirements of the weaned pig are met; the mixed feed has good palatability and a high digestive rate and can reduce various discomforts caused by weaning stress, enhance the immunity of the weaned pig, improve food consumption and productivity of the weaned pig, promote rapid and healthy growth of the weaned pig and guarantee the survival rate of the weaned pig.