The invention discloses propofol fat emulsion injection and a preparation method thereof. The propofol fat emulsion injection comprises, by weight percent, 1% of propofol, 6-8% of soybean oil, 1.5-2.0% of soybean lecithin, 3-5% of glycerol, 0.1-0.8% of tween-80, 0.05-0.1% of phosphoric acid, appropriate amount of pH regulator and the balance of water for injection, wherein the amount of the pH regulator is enough to regulate pH of the water for injection to 7.5-8.0. The propofol fat emulsion injection improves drug delivery, decreases particle size, and improves uniformity of particle size, and accordingly stability of the injection is improved, pain during injection is lowered, and drug dependency of patients is increased.