The invention discloses a krill oil microcapsule powder and a preparation method thereof. The method comprises the following steps of: preparing an oil phase solution and an aqueous phase solution, mixing, emulsifying, homogenizing and drying the two solutions. The krill oil microcapsule powder is prepared from the following raw materials in percentage by weight: 0.001-90 percent of krill oil, 0.001-10 percent of oil-phase antioxidant, 0.5-90 percent of wall material, 0.001-5 percent of aqueous phase antioxidant, 0.001-5 percent of aqueous phase stabilizer, 0.001-5 percent of antitackiness agent, 0-5 percent of edible essence and 0.01-99 percent of filling agent. The krill oil coated by the krill oil microcapsule powder is high in content, high in stability and high in liquidity; in addition, the krill oil can be completely dispersed in water in an nm microparticle form after rehydration and is stably preserved for a long time, and the phenomena of floating oil, precipitation and bottle adhesion are avoided. The application range of the krill oil is widened, and the krill oil can be applied to the fields of dry-blending, beverages, dairy products, baking, tablets and the like. No waste residue, waste gas and waste water are generated in the production process, the production process is environmentally-friendly and simple, and the industrialization is easy and feasible.