Yb:Ho:LiNbO3 crystals tridoped with various Zr4+ concentrations (0, 1, 2 and 5 mol%) were grown by Czochraski technique. Defect structure and dopant occupancy of Zr:Yb:Ho:LiNbO3 crystals were determined by IR transmission spectrum. The effective distribution coefficient of Zr ion increases with increasing ZrO2 concentration in the melts, which is near to one. The light-induced scattering of Zr:Yb:Ho: LiNbO3 crystals was quantitatively measured via the incident exposure energy. The exposure energy of Zr (5 mol%):Yb:Ho:LiNbO3 crystal is 49.33 J/cm(2), which is two orders higher than that of Yb:Ho:LiNbO3 crystal in magnitude. The photoconductivity is key factor to understand the internal relationship between the dopant occupancy and exposure energy of the crystals. (C) 2014 Published by Elsevier Ltd.