The invention provides nutritional health dried sweet potatoes and a preparation method thereof, belonging to the technical field of food processing. The dried sweet potatoes comprise the following raw materials: sweet potatoes, walnuts, cape jasmine, lucid ganoderma, astragalus membranaceus and red ginseng. The dried sweet potatoes have medicinal functions of promoting brain activation, benefiting the brain, developing intelligence, promoting sleep, beautifying and moistening skin, delaying brain aging function, replenishing inhibitory neurotransmitter of a human body, well reducing blood pressure, promoting improvement and protection of kidney function, inhibiting fatty liver, activating liver function, improving the immunity of the human body, resisting radiation, inhibiting tumors and the like; meanwhile, by adopting a unique preparation process, the original nutrition and specific flavor of the sweet potatoes can be kept, the energy resources can be saved, the waste can be reduced, the processing time can be shortened, and the efficiency can be improved.