We investigated the time-dependent change of Hyper-Rayleigh Scattering (HRS) from silver nanoparticle aggregates induced by the addition of salt: NaCl and NaNO3. The observed HRS intensity showed very different response depending on the added salt, whereas the linear light scattering showed similar time-dependence. We showed that the difference in the HRS time-profile should be mostly related with the difference of nanoparticle surface layer, rather than with the difference of the aggregate size and structures. Possible precipitation of newly formed AgCl layer on the nanoparticle surface may play a significant role in the dramatic change of HRS for the NaCl addition. (C) 2014 Elsevier B.V. All rights reserved.