Doxorubicin-loaded nanoparticles, using doxorubicin (ADM) as model drug and vinylpyrrolidone as matrix, were prepared by inverse emulsion polymerization in the paper. The nanoparticles were characterized by telescope electron microscopy (TEM), laser light scattering technique (LLS) and infrared spectrum (IR). LIS test showed that the optimal prepared ADM-loaded nanoparticles had an average size 18.8nm and a narrow size distribution between 15nm and 32nm, which was consistent with the result obtained by TEM. And IR results indicated that the nanoparticles consisted of ADM and polyvinylpyrrolidone (PVP).