Based on the local field enhancement of noble metals, the effect of silver nanoparticles on spectroscopy properties of rhodamine B was investigated by transmission electron microscopy and UV-Visible spectroscopy and spectrofluorophotometer. Furthermore, the interactions among electrolyte ions and silver nano-particles and rhodamine B were studied. The results indicate that the fluorescence of rhodamine B increased first and then decreased when the silver nanoparticles were added into the 0.6 μmol·L－1 rhodamine B. The fluorescence of rhodamine B always decreased when the concentration of rhodamine B is over 0.6 μmol·L－1. The electrolytes, including KNO3, KCl, Ca(NO3)2, MgCl2and CaCl2, led to the formation of large particles and aggregates in the solution. The effect order of electrolytes on the aggregates of silver nanoparticles is CaCl2>MgCl2>KCl>Ca(NO3)2>KNO3. With the increasing of the electrolyte content, the fluorescence intensity decreased first and then increased until to the constant value. The dependence of electrolytes on the fluorescence intensity of the rhodamine B -Ag solution follows the order of Ca(NO3)2>CaCl2>MgCl2>KCl>KNO3.