We present a theoretical framework to calculate the electrochemical charge on silica surfaces in contact with high-ionic-strength solutions in narrow channels. Analytical results indicate that the contribution of the adsorbed metal cations to the total surface charge is not negligible when the salinity is larger than 1 mM. The electrical triple-layer model is proved much better than other models for high ionic strength, The charge regulation caused by the double-layer overlap in narrow channels will reduce the surface charge density but increase the zeta potential on silica surfaces. Published by Elsevier Inc.