To establish the fingerprints of Euodiae Fructus and prepared Euodiae Fructus,the changes of chemical components in Euodiae Fructus and its preparation were analyzed by multivariate statistics. Using ultra high performance liquid chromatography (UPLC) technology. Chromatographic column was YMC Triart C₁₈ (100 mm×2.1 mm,1.9 μm).The mobile phase consisted of acetonitrile-0.1% phosphoric acid water (gradient elution),the flow rate was 0.30 mL/min,the column temperature was 30 ℃,the detection wavelength was 254 nm,the injection volume was 1 μL.The UPLC fingerprints of Euodiae Fructus and its preparation were established,and the similarity calculation and orthogonal partial least squares discriminant analysis (OPLS-DA) were used to analyze and evaluate the fingerprints,the variable importance projection (VIP) value greater than 1 was used as the criterion to screen the differential components before and after processing. Taking the average peak area as the variable,the average peak area of the chromatographic peaks of different components of Euodiae Fructus and prepared Euodiae Fructus was tested by paired t-test. A total of 27 common fingerprint peaks were identified in the fingerprint of Euodiae Fructus,Eight chemical components were identified as neocrogenic acid,chlorogenic acid,cryptochlorogenic acid,caffeic acid,hyperin,dehydroevotaine,rutaecarine and rutaecarine. Glycyrrhizic acid chromatographic peak was added to the fingerprint of processed Euodiae Fructus. The results of similarity degree showed that the similarity degree of Jiangxi production area was low. Hunan production area was lower. Guangxi production area was relatively high. Orthogonal partial least squares discriminant analysis (OPLS-DA) found six markers of difference,and the order of significance of difference was glycyrrhizic acid > evocorine > peak 3> peak 1> chlorogenic acid > peak 2. Except that glycyrrhizic acid is a new component,the contents of the other five chemical components of Euodiae Fructus after processing are reduced to a certain extent. After the processing of Euodiae Fructus,the average peak area of peak 21 (evodiamine) decreased significantly (P<0.05),peak 28 (glycyrrhizic acid) was a new component,and the average peak areas of the other five differential chemical components decreased in varying degrees,but there was no significant statistical significance. This analysis method has strong specificity and good repeatability. It preliminarily discusses the correlation between the pharmacological effects and chemical components of Euodiae Fructus and prepared Euodiae Fructus,and explains the relationship between the changes of pharmacological effects and chemical components before and after Euodiae Fructus processing to a certain extent,which can provide data reference for the quality and processing research of Euodiae Fructus and prepared Euodiae Fructus.