Abstract Potassium titanyl phosphate (KTiOPO 4 or KTP crystal) is a quadriatomic target made of O, P, K and Ti. Xe ions were implanted in amorphous potassium titanyl phosphate at energies from 50 to 400 keV. The range profiles of Xe ions implanted in KTP were analyzed by Rutherford backscattering of 2.1 MeV He ions. The mean projected ranges and range stragglings are compared with our calculated value based on Biersack's angular diffusion model and Monte Carlo simulation. The results show that the obtained mean projected range is in good agreement with our calculated value, the range straggling is higher than the calculated value. But significant deviation from the transport of ions in matter (TRIM'89) prediction is found.