The process of x-ray diffraction on the La 3 Ga 5 SiO 14 (LGS) crystal modulated by surface acoustic waves (SAWs) near the K absorption edge of Ga (E ¼ 10 367 eV) was studied. A redistribution of the diffracted x-ray intensity between the diffraction satellites occurs at the absorption edge due to the change in the x-ray penetration depth into the crystal and an effective change in the interaction of x-ray radiation with the near-surface crystal region modulated by SAW. The intensity distribution of the diffraction satellites starts to change smoothly immediately after the K absorption edge of Ga with a decrease in the x-ray penetration depth into the crystal.