Abstract: The fluorescent polyphosphazene nanoparticles (PZF) were fabricated via precipitation polymerization of hexachlorocyclotriphosphazene (HCCP) and fluorescein (FL) under ultrasonic irradiation at room temperature by using triethylamine (TEA) as acid acceptor and acetonitrile as solvent. Fourier Transform Infrared Spectroscopy (FT IR), Energy Dispersive Spectroscopy (EDS), Scanning Electron Microscope (SEM) and Transmission Electron Microscope (TEM) were used to characterize the chemical structure and elements of nanoparticles. Results showed that the nanoparticles were spheres with a uniform diameter and had excellent fluorescent emission property. By exposing PZF under 365 nm UV for different irradiation time， the fluorescent intensity did not lower much, which indicated that PZF had excellent photobleaching stability. Key words:fluorescein; polyphosphazene; nanoparticles; fluorescent property