This paper presents results and observations obtained from a study of crystallization effect on optical property by doping Sm2O3 in amorphous material. The heat treatments, according to Differential Thermal Analyzer (DTA) results, have been performed in order to generate crystallization of amorphous material. The crystalline phase has been analyzed by X-Ray Diffractor (XRD). In this work, we have observed the emission intensity changes by increasing the concentration of Sm3+ ions up to 1.0mol%. As a result, we have confirmed the solubility of RE dopant in this composition glass by comparing the emission intensity at three strong emission bands [4G5/2-6H5/2 (564 nm), 4G5/2-6H7/2 (602 nm) and 4G5/2-6H9/2 (647 nm)]. Beside, the up-conversion of photoluminescence by the optimum crystalline size of host matrix has been shown by Fluorimeter data. In conclusion, we have estimated the effect of crystalline on optical property in amorphous matrix from this research.