The invention provides an immunity-enhancing ginseng polysaccharide oral liquid, prepared from, by weight, 200-400 parts of ginseng polysaccharides, 40-90 parts of arginine, 20-70 parts of taurine, 1-4 parts of acesulfame-K, 1-3 parts of lysine, 1-3 parts of nicotinamide, 1-4 parts of potassium sorbate, 1-2 parts of vitamin B6, 1-2 parts of vitamin B12, and 200-300 parts of purified water. The invention also provides a preparation method of the ginseng polysaccharide oral liquid. The prepared ginseng polysaccharide oral liquid has unique aroma of ginseng, is fresh and cool in taste, is sour and sweet, has coordinated and pleasing color, aroma and taste, is highly acceptable, and has the effects of enhancing immunity, resisting tumors, fighting thrombus, improving body intestinal micro-ecological balance, lowering blood glucose, lowering cholesterol, delaying senility, resisting fatigue and the other effects.