The invention discloses a method for extracting madecassic acid from herba centellae. The method includes the following steps of firstly, smashing herba centellae, conducting reflux extraction through an ethyl alcohol solution with volume concentration of 60-70 v%, filtering an extraction solution, recovering solvent from filtrate, adding water at 40-50 DEG C for dissolving and filtering, and dissolving filter residues in an ethyl alcohol solution with volume concentration of 50-60 v% to obtain a crude extraction solution; secondly, adding rare-earth salts to the crude extraction solution to be mixed and evenly stirred to obtain mixed liquid; thirdly, applying the mixed liquid to an X-5 type macroporous resin column, conducting water washing till being colorless, conducting eluting through ethyl alcohol with volume concentration of 20-30 v%, conducting thin layer chromatography tracking and detecting, collecting ethyl alcohol eluent containing asiatic acid, conducting eluting through ethyl alcohol with volume concentration of 40-50 %, conducting thin layer chromatography tracking and detecting, collecting ethyl alcohol eluent containing madecassic acid, recovering ethyl alcohol, and conducting drying to obtain madecassic acid. The extracted madecassic acid is high in purity and high in yield.