To perform a study of the medicinal herbal microscopic and molecular identification of Rheum nobile radix and rhizome.Methods：The cross sections of Rheum nobile radix and rhizome were obtained by using paraffin sectioning,and temporary glycerol tablets with chloral hydrate were used to identify the microscopic structure of powder.The matK gene sequence analysis technique was used for molecular identification of Rheum nobile.Results：In the cross-section of radix,both the cortex and xylem were wide with vessels arranging radially and massive calcium oxalate crystal visible in parenchyma cells.Pith part was broad without any abnormal vascular bundle.Powder contained a mass of calcium oxalate crystals whose edges were mostly short blunt.There were lignified vessels and small starch grain as well.The length of matK gene sequence of Rheum nobile was 1 524 bp.Upstream of matK sequence,there were ten base-pair substitutions in 106,218,222,365,522,615,711,759,801,852,and 6 bases CAAGAA inserted in 950-955.Conclusion：The research tends to contain relatively comprehensive identification information of Rheum nobile.These microscopic features can be used as evidence for identification of Rheum nobile radix and rhizome,and the matK gene sequence analysis helps lay a foundation for Rheum nobile DNA barcoding research.