The invention discloses a method for extracting and comprehensively utilizing anthocyanidin from Ipomoes batatas. The method comprises the following steps: cleaning the Ipomoes batatas, immersing, fragmenting and mashing the Ipomoes batatas under weak acid and normal temperature conditions, separating batata slag, naturally precipitating, taking an upper layer aqueous solution of anthocyanidin, filtering twice and carrying out membrane filtration, and adsorbing, eluting and concentrating a filtrate to obtain a pasty anthocyanidin product; 2, processing the pasty anthocyanidin product with a routine method to obtain a solid anthocyanidin product; 3, washing precipitated and filtered starch with water, and processing with a routine method to obtain a starch product; 4, carrying out mother solution processing which comprises controlling the pH value of the mother solution at 4.0-4.2 and controlling the pH value of the mother solution at 4.4-4.5 after filtering, sending an upper solution to a fragmentation and mashing operation, carrying out reduced pressure concentration on a lower layer sol, and processing with a routine method to obtain a protein product and a mucopolysaccharide product; and 5, recovering separated water, a separated mother solution or a separated organic solvent, and processing waste residues with a routine method to obtain a forage and a fertilizer. The method of the invention has the advantages of chemical reagent and water consumption reduction, product yield improvement, comprehensive utilization of the Ipomoes batatas, added value improvement, and good social benefit and environmental protection benefit.