In this paper,the nanometer-sized(200 nm)quaternary rare-earth complex Eu(BA)(TTA)2phen was successfully prepared by using the method of optimizing chemical precipitation.The characterizations of these nanoparticles were performed by using elemental analysis,thermogravimetric analysis,infrared spectroscopy,fluorescence spectroscopy,transmission electron microscopy and luminescence quantum-yield.The results indicate that they are better than common ternary complexes at light-emitting performance,luminescence properties,thermal stability,uniformity and particle size;they can also be further mixed with a suitable polymer to form functional rare earth polymers.Compared to the common solid materials,the quaternary complex has better and unique characteristics such as nanoparticle size effect and surface effect.A foundation had been laid for the further expansion of its application in the field of light-emitting and magnetic materials. In this paper, the nanometer-sized (200 nm) quaternary rare-earth complex Eu (BA) (TTA) 2 phen was successfully prepared by using the method of optimizing chemical precipitation. Character character of these nanoparticles were performed by using elemental analysis, thermogravimetric analysis, infrared spectroscopy, fluorescence spectroscopy, transmission electron microscopy and luminescence quantum-yield. These results are that that are better than common ternary complexes at light-emitting performance, luminescence properties, thermal stability, uniformity and particle size; they can also be further mixed with a suitable polymer to form functional rare earth polymers. The quaternary complex has better and unique characteristics such as nanoparticle size effect and surface effect. A foundation had been laid for the further expansion of its application in the field of light-emitting and magnetic materials.