The invention discloses multi-flavor instant nutritional crispy food and a preparation method thereof. Raw materials of the instant food are rich in variety and comprise fungi, vegetables, fruits and beans. The method comprises the steps of harvesting, sorting material, refrigerating, washing, refining, flavoring, cooking, carrying out quick freezing, frying, deoiling, cooling, checking and packaging and the like, thereby finally preparing the multi-flavor instant nutritional crispy food. According to the multi-flavor instant nutritional crispy food and the preparation method thereof, the raw materials are dehydrated and dried by adopting a low-temperature vacuum frying process, and the whole frying process is carried out under the condition of vacuum low temperature, so that free moisture and bound moisture in the raw materials will be subjected to sudden gasification, swelling, evaporation and blowoff, rapid drying and dehydrating can be achieved, and meanwhile, nutrients in the raw materials are reserved to the maximum; in addition, the multi-flavor instant nutritional crispy food disclosed by the invention is free of any food additive and is healthy food applicable to various consumer groups.