For a problem that the variety of the peony cannot be quickly classified in the prior art, the invention provides a peony variety classification method and system without pretreating a sample. The method comprises the following steps: performing color classification on to-be-classified petals, wherein the technical scheme is as follows: if the color classification cannot determine the category, placing a to-be-classified peony petal on a sample movement control platform, directly etching one side of the petal of the to-be-classified peony through a laser-induced breakdown spectrum system, andgenerating plasma on the surface of the to-be-classified peony, wherein the plasma radiation light is split through a spectrograph, thereby obtaining the constituent and content information of the petal of the to-be-classified peony through photoelectric conversion and signal processing; comparing with a peony variety spectrum database according to the spectrum data, and determining the variety ofthe to-be-classified peony. The peony spectrum information can be quickly and accurately detected, thereby realizing quick and automatic classification of the peony variety.