The invention provides an extraction method of a tobacco leaf polysaccharide extract. The method comprises the following steps of (A) sequentially performing deactivation of enzymes, drying and pulp grinding on No.10 Yuyan tobacco leaves to obtain tobacco leaf pulp; (B) sequentially performing complex enzyme enzymolysis, ultrasonic treatment and concentrated alkaline extraction on the tobacco leaf slurry to obtain tobacco leaf polysaccharide extract liquid; (C) concentrating the tobacco leaf polysaccharide extract liquid; then, performing alcohol deposition and refining to obtain the tobacco leaf polysaccharide extract. The No.10 Yuyan tobacco leaves are used as extraction raw materials; the tobacco leaves are subjected to sufficient pulp grinding treatment; the complex enzyme is used for degrading the cell walls; the goal of damaging the cell structures to a great degree is achieved, so that the polysaccharide extraction rate is increased. On the other hand, the polysaccharide molecules can be degraded to a certain degree though ultrasonic treatment; the water solubility of the polysaccharide is increased, so that the extraction rate is increased. The tobacco leaf polysaccharide obtained by the method has the advantages of high purity, high solubility, high safety and no pollution, and can be applied to food fresh keeping.