Abstract: Gamma-ray densitometers are widely used in industry due to their insensitivity to the measured medium and convenient installation. The gamma-ray radioactive source is the core component of the gamma-ray densitometer. The traditional preparation method involves high-temperature ceramicizing the source core that adsorbs radionuclides and then sealing it in the source shell. This method is faced with problems such as poor adsorption performance of zeolite molecular sieves, complicated processes, and high radioactive pollution.In response to the problems faced by traditional methods, this study has synthesized CeO₂, a source core material with better performance, and innovatively proposed a triple safety protection structure of source shell-high-temperature adhesive-source core. Experimental data show that the vibration integrity rate of the CeO₂ source core is 100%, the saturated adsorption rate is 85%, the leaching rate is 23%, the blocking rate of the source core and the source shell is 5.28%, and the sealing integrity rate of the source shell is 100%. All aspects of the indicators are significantly better than those of radioactive sources prepared by traditional methods.This study provides a new method for the preparation of radioactive sources, which has the advantages of simple process, high safety, environmental friendliness, and low scattering.