The invention belongs to the technical field of traditional Chinese medicine quality standard detection, and discloses a quality detection method for prepared radix polygonum multiflorum thunb. The quality detection method for the prepared radix polygonum multiflorum thunb is characterized in that the fingerprint, the DPPH (1,1-diphenyl-2-picrylhydrazyl) scavenging activity finger-print and the active common peak of the of prepared radix polygonum multiflorum thunb are subjected to spectrum effect correlation researching on the basis of a HPLC (High Performance Liquid Chromatography)-DPPH combined technology, the oxidation resistance effect of the prepared radix polygonum multiflorum thunb is used for judging the quality of the prepared radix polygonum multiflorum thunb, and a scientific and perfect oxidation resistance quality evaluation and control standard for the prepared radix polygonum multiflorum thunb is established. The quality detection method disclosed by the invention has the advantages of being quick in response, visual in results, accurate in determining the nature, simple in operation and good in reproducibility.