The invention belongs to the technical field of solid beverages, and particularly relates to a composite enzyme cellulose solid beverage and a preparation method thereof. The composite enzyme cellulose solid beverage is prepared from the following raw materials in percentage by mass: 40 to 50 percent of psyllium seed husks, 20 to 30 percent of sorbitol, 5 to 10 percent of a malt extract, 5 to 10 percent of microcrystal cellulose, 0.01 to 0.03 percent of calcium silicate, 5 to 10 percent of wheat fibers, 5 to 10 percent of apple fibers, 1 to 5 percent of konjac glucomannan, 1 to 5 percent of black bean fibers, 2 to 5 percent of composite enzyme, 0.05 to 0.1 percent of a sweetening agent, and 1 to 5 percent of essence. The composite enzyme cellulose solid beverage is prepared by compositingthe composite enzyme and various plant dietary fibers, and is rich in nutrition ingredients, good in weight loss efficacy, good in instant solubility, capable of being instantly dissolved in cold water, stable under certain high-temperature and high-humidity condition, and capable of improving the drinking experience of a drinker.