Ketamine is a common new type of drug. According to the chirality of the C atom connected to 2-chlorophenyl, ketamine has chiral isomers ofR and S-ketamine. Due to the similarity of physical and chemical properties of the two isomers, it is difficult to distinguish them by traditional chromatographic methods. To reveal the differences between ketamine isomers and the rapid identification and characterization of ketamine,experimental combined theoretical calculations were used to investigate their properties in this article.The structure optimization of R and S-ketamine chiral isomers was carried out by B3LYP/6-311++G (d,p), and the single point energy was calculated at the MP2/aug-cc-pVTZ level. The calculation of surface electrostatic potential and molecular polarizability shows significant specificity in the properties of the two isomers, leading to their different Raman properties. Using standard samples, Ketamine Raman spectroscopy was experimentally obtained, and the characteristic peaks were determined to be 1 044, 654 and 1 590 cm-1, which are in good agreement with theoretical calculations, while the characteristic peaks of 457 and 596 cm-1 can be used to distinguish between R and S-ketamine. The differences in Raman properties of isomers were explained by electronic structure and polarization analysis, and the Raman vibrational peaks were assigned by PED analysis. Due to the isomers and special double hexagonal ring structure, the study of ketamine Raman spectroscopy is relatively complex. This article provides accurate experimental data and reliable theoretical support for the rapid detection of ketamine Raman spectroscopy, which will contribute to the formulation of ketamine Raman detection standards and the establishment of drug Raman spectroscopy databases. It will also provide a reference for the study of differences in the spectral properties of chiral isomers.