Photobleaching effect is an immense problem in optical spectroscopy, especially when fluorophores are adsorbed on metal nanoparticles (NPs). Nevertheless, little effort has been assigned to the study of fluorophore photostability under this condition. In this paper, the effect of photobleaching on the Raman signal enhancement factor (RS‐EF) of dye molecules on Ag‐modified silicon nanowire (SiNW) substrates is investigated. For this purpose, SiNWs are fabricated by using the vapor–liquid–solid growth mechanism and decorated with Ag NPs by means of electroless deposition method. This process provides the possibility of forming uniformly and tightly packed Ag NPs on SiNWs. The effect of photostability of the crystal violet as analyte molecules on surface‐enhanced Raman spectroscopy is investigated as a function of time evolution and laser power. The influence of Ag NP deposition time on Raman signal enhancement is explored. Our work shows how we can optimize the excitation power for achievement of higher RS‐EF and, consequently, lower detectable concentration. Time evolution of surface‐enhanced Raman spectroscopy signal shows an exponential decay behavior, which indicates an almost uniform distribution of EFs. Capability of our nanostructure is assessed for different concentration, and subsequently, limit of detection of 10 pm with RS‐EF of 2.4×109 is obtained. Copyright © 2017 John Wiley & Sons, Ltd.