The purpose of this paper is to investigate infrared transtions of Er

3+

and Tm

3+

ions and energy transfer between them in LaOBr material.Jouart has studied energy transfer between Er

3+

and Tm

3+

ions in cadimium fluoride crystals

[1]

.But there are no publishes about energy transfer between Er

3+

and Tm

3+

ions in rare earth material in the infrared region so far.Here we present the results for energy transfer between Er

3+

and Tm

3+

ions in the LaOBr material for the first time.We find that there are a number of luminescence lines of Er

3+

and Tm

3+

ions jn the infrared region from 0.8μ to 2.0μ by the excitation of 5145Åor 4880Åof argon laser.They come seperately from four energy levels of Er

3+

and Tm

3+

ions.The intensities of fluorescence of Er

3+

and Tm

3+

ions strongly depend on the concentration of Er

3+

and Tm

3+

ions.Coresponding to emission lines from different energy levels of ions

the laws of concentration quenching are different.This kind of self-quenching phenomenon may be related with the interactions of multipolar cross relaxation of Er

3+

and Tm

3+

ions energy levels.Our results provide an information to look for the best doping-con-centration of infrared transitions of this kind of material.