The invention relates to the technical field of antibacterial gel, in particular to antibacterial gel and a preparation method thereof. The antibacterial gel per liter comprises the following raw materials: 1.7-1.9g benzalkonium chloride, 30-50ml glycerol, 0.1-1.3g menthol, 1-1.8g alums, 0.3-0.4g lactic acid, 2.5-5g carbomer, 3-6g traditional Chinese medicine extract and the balance of purified water. The antibacterial gel contains various anti-inflammatory, antibacterial and analgesic components; an antibacterial effect is best through a synergistic effect of the raw materials; the biocompatibility of the antibacterial gel meets GB / T 16886.11-2011; a microbiological indicator of the antibacterial gel meets GB 15979-2002; and the antibacterial gel is suitable for nursing of various vaginal bacterial infection, trichomonas infection, leukorrhea, monilial infection, cervix and genital tract or mucosal wound surface infection, promotes healing of a wound surface after cervical erosion physiotherapy, and is further suitable for internal hemorrhoid, external hemorrhoid, mixed hemorrhoid, anal fissure and anorectal postoperative nursing.