The invention discloses a pitaya enzyme beverage and a preparation method thereof. The objective of the invention is to provide the pitaya enzyme beverage and the preparation method thereof. The pitaya enzyme beverage is prepared by using pitaya, lemon, white granulated sugar, honey, rock candy, low-fat milk powder, lactobacillus, acetic acid bacteria, fruit juice, purified water and saccharomycete, the proportion of pitaya, lemon, white granulated sugar, rock candy, lactobacillus, acetic acid bacteria and saccharomycete in pitaya enzyme is 10 parts:2 parts:1 part:1 part:0.5 part:0.5 part:0.5part, and the blending proportions of fruit juice, honey, low-fat milk powder and pitaya enzyme in the pitaya enzyme beverage are 10:1, 4:1 and 2:1. By material processing and three times of fermentation, the pitaya enzyme beverage which has unique and rich taste is prepared, the anthocyanin of pitaya pericarp is kept to a great extent, the needed fermentation period is short, production is easy,the beverage is suitable for mass production, and moreover, the pitaya enzyme beverage can be used in a lot of ways, and is good for the physical health of people.