The results of spectral observations of the symbiotic star AG Pegasi (AG Peg) are pre-sented. The spectra of the star AG Peg were obtained with a spectral resolution of R = 28000 during the period of 2016-2019, in the wavelength range λ = 3900–8000 Å. Based on the AAVSO (American Association of Variable Star Observers), data for the period 1954-2022, a periodicity in the star's brightness changes was identified, with a period of about 815 days. The behavior of selected spectral lines in different phases of the orbit of the AG Peg binary system is described as follows. Profiles of the considered emission lines show strong variability, with a complex structure - single-peaked, double-peaked, and intermediate between them. In general, their variability does not show dependence on the orbital period of the AG Peg binary system. The change in the radial velocities of the absorption lines and the temperature of the hot component corre-sponds to the light curve of the star AG Pegasus, constructed for a period of P = 815 days, which we found from photometric data.