Gatifloxacin is widely used as a fourth-generation fluoroquinolone antibiotic, and it has drug residues in humans and livestock, which endangers everyone’s life and health. In order to avoid secondary intake, it is particularly important to be able to detect the presence of gatifloxacin residues in meat products quickly.To this end, this paper uses vibrational spectroscopy combined with density functional theory to provide basic data for the vibrational spectroscopy detection and identification of gatifloxacin and provides a reference for its application in the field of drug detection. The specific research contents and results are as follows: The first step is to construct the molecular structure of gatifloxacin based on Density functional theory (DFT), and optimize the structure by using B3LYP/6-311+G(d) basis set. Calculate its theoretical Raman and infrared spectra. Theoretical calculations show that the gatifloxacin molecule has obvious Raman and infrared activity in the range of 3 700~2 800 and 1 800~400 cm-1. The former is mainly the vibration of the upper group of the functional group, and the latter is the fingerprint area. The vibration of the upper button. Due to the superiority of the complementary information of the two kinds of spectral information, firstly, by comparing the theoretical Raman spectrum and the infrared spectrum, the vibration peak frequency of two or only one vibration activity is marked, and the Gaussian view is combined with each of the gatifloxacin molecules. The vibration frequency corresponding to each key is fully attributed, and the spatial structure parameters such as the bond length, bond angle and dihedral angle of the gatifloxacin molecule are given. In the second step, the natural Raman spectroscopy (NRS) and infrared spectroscopy (IR) of Gatifloxacin (Gati) were measured experimentally. The theoretical calculation result error is corrected by the frequency correction factor of 0.977 and compared with the experimental data. In the fingerprint area, the Raman and infrared characteristic peak wave number matching degree are good. The peak wave number difference is mostly in the range of 0~10 cm-1. The calculation results are basically consistent with the experimental data. The results provide basic data for the vibrational spectrum detection and identification of gatifloxacin, and provide a reference for its application in the field of drug detection.