The invention discloses an antibacterial whitening mouthwash and a preparation method thereof. The antibacterial whitening mouthwash comprises an antibacterial component and a mouthwash matrix component, wherein the antibacterial component comprises 0.05 to 0.5 part of lysozyme, 0.01 to 0.5 part of lauryl arginine ethyl ester hydrochloride, 0.01 to 1 part of dextran anhydrase and 1 to 10 parts ofabelmoschus manihot extract. A substrate component of the mouthwash comprises one or more of an emulsifier, a moisturize, a flavoring, an acid-base conditioner and an essence, and the balance is deionized water. Lysozyme and lauryl arginine ethyl ester hydrochloride are dissolved in a citric acid solution and uniformly stirred; the prepared ingredients are mixed with the emulsifier, moisturizer, flavoring and essence evenly, pH is adjusted, and abelmoschus manihot extract and dextran enzyme are added. The invention makes the synergistic effect between the natural antibacterial agent and the chemical antibacterial agent exist, and the mouthwash produced by the invention has high safety and good antibacterial activity, and can effectively prevent and control the occurrence of dental plaque and oral inflammation.