In the present paper, the photoluminescence of silver nanoparticles with different size and surface modifier was studied. The results show that the strong emission peak at 362 nm and the two weak emission peaks at 592 and 725 nm respectively were observed by excitation at different wavelengths. With increasing excitation wavelength, the intensity of emission peak decreased and the emission peak at 362 nm red-shifted. Otherwise, the photoluminescence of silver nanoparticles was sensitive to the excitation light of 210 nm. The emission peak has little relation with the surface modification and particle size of silver nanoparticles, just as the particle size decreased, the intensity of peak decreased. The intensity of emission peak decreased with the slit width decreased. The emission peaks gradually gathered together and merged into single peak at 426 nm, and the intensity first increased and then decreased. The mechanism of photoluminescence of silver nanoparticles was discussed by absorption-reemission of photoelectrons and interface energy hybridization.