Schizonepetae Herba and Schizonepetae Spica were analyzed to provide a basis for its quality evaluation and clinical application.In this study,Schizonepetae Herba and Schizonepetae Spica were collected from different sources on the market.First,the total volatile oil of the samples was extracted by steam distillation,and the volatile oil composition and content in Schizonepetae Herba and Schizonepetae Spica samples were determined by GC-MS;Second,principal component analysis and cluster analysis were used on the relative content of the common components of the volatile oil in Schizonepetae Herba and Schizonepetae Spica by the SIMCA14.1 software.Finally,OPLS-DA combined with t-test were used to test and screen differential metabolic markers of volatile oil in Schizonepetae Herba and Schizonepetae Spica.The result shows that the total content of volatile oil in Schizonepetae Herba is generally lower than Schizonepetae Spica,and it is extremely significant that the content of volatile oil in Schizonepetae Herba and Schizonepetae Spica is different.Moreover,the kind of volatile oil in Schizonepetae Herba is more than that in Schizonepetae Spica.Schizonepetae Herba and Schizonepetae Spica are differences in composition characteristics,and they are grouped into one category,respectively.The OPLS-DA results combined with t-test indicates that there are 10 kinds of main metabolic markers including menthone,isopulegone,β-caryophyllene,limonene,β-pinene,pulegone,carvol,cis-p-2,8-menthol,1-octene-3-ol and 4-isopropenyl toluene that cause the difference between the two pieces of decoction.Therefore,there are differences in the chemical quality characteristics of the volatile oils of Schizonepetae Herba and Schizonepetae Spica,and the correlation between the difference and its clinical efficacy remains to be further studied.