The invention provides an extraction purification method of aconitum carmichaeli polysaccharides. The extraction and purification method comprises following steps: a, raw aconitum carmichaeli or processed aconitum carmichaeli are smashed and sieved, an obtained powder is added into 95% ethanol for warm immersion for 3 to 6h, and filtering is carried out so as to obtain a filter residue 1; b, the filter residue 1 is extracted with purified water for 1 to 3h at 80 to 100 DEG C, and filtering is carried out so as to obtain a filtrate; c, the step b is repeated for 1 to 2 times, and obtained filtrate is mixed; d, the mixed filtrate is subjected to evaporation at 55 to 65 DEG C until 10 to 20% of the mixed filtrate is left, and the left mixed filtrate is cooled to room temperature; e, 95% ethanol is added with stirring until the ethanol content of an obtained solution ranges from 65 to 85%; f, the solution is allowed to stand for 12 to 24h at 4 DEG C, filtering is carried out, filtrate is discarded, and an obtained filter residue 2 is collected; g, the filter residue 2 is washed with absolute ethyl alcohol, acetone, and ether respectively for two times, and a left residue is subjected to vacuum drying at 50 to 60 DEG C so as to obtain aconitum carmichaeli polysaccharide powder. The invention also provides the aconitum carmichaeli polysaccharides prepared via the extraction purification method, and applications of the aconitum carmichaeli polysaccharides. The extraction purification method is simple, high in extraction rate, and low in cost; and it is confirmed by pharmacodynamic experiment that the obtained aconitum carmichaeli polysaccharides are capable of preventing spleen deficiency diarrhea, and improving immunity.