Objective: The preparation of polysaccharide from Schizonepeta tenuifolia and its effects on the antibacterial activity of the juice of lily-schizonepeta -pear were studied, in order to expand its application in drinks. Methods: The optimal preparation technology of polysaccharide from S. tenuifolia was studied by orthogonal test. The effect of schizonepeta polysaccharide on antimicrobial activity of the juice of lily-schizonepeta -pear was determined by filter paper disc-agar diffusion method. Results: The results showed that the optimal extraction conditions of schizonepeta polysaccharide were as follows: solid-liquid ratio 1∶30 (g/mL), temperature 60 ℃, extraction time 2 h. The extraction yield of polysaccharide was (29.43±0.16) mg/g under the extraction conditions. The results showed that the juice had little effects on Penicillium and Yeasts, while could strongly inhibit Escherichia coli, Bacillus subtilis and Staphylococcus aureus. By compared the bacteriostatic effects among the three kinds of juice, i.e., juice of lily-schizonepeta -pear, schizonepeta polysaccharide and lily-pear, the antibacterial effect of lily-schizonepeta-pear juice was the highest, followed by schizonepeta polysaccharide juice and then lily-pear juice. Conclusion: The polysaccharide from S. tenuifolia enhanced the antibacterial activity of the lily-schizonepeta-pear juice.