Bimetallic Ag/Pd nanoparticles with various the concentration ratios of the additional silver ions to palladium ions (CAg+/CPd2+) have been prepared by the self-regulated reduction in the refluxing of sodium n-dodecyl sulfate aqueous solution without additional reducers. The particular size of prepared bimetallic nanoparticles from ∼6.0 to ∼2.6 nm is dependent on CAg+/CPd2+. Additionally, surface plasmon resonance spectra confirm that the prepared bimetallic nanoparticles are Pd shell-riched structures. As supported by the in situ analysis of quartz crystal microgravimetry, the prepared bimetallic nanoparticles can be successfully used as new activators and have the excellent activity for electroless nickel bath. Keywords: Nanoparticle, Palladium, Electroless copper deposition, Kinetics, Electroless nickel deposition, Bimetallic, Activator, Silver