The kinetics related to an electroless Ni–P deposition on quartz surface was monitored by an electrode-separated piezoelectric sensor (ESPS). It was shown that the mass changes during the initial grease removing and quartz coarsening processes follow the exponential decay and linear decrease models, respectively. The initial Ni–P plating process consists of four stages: an induction period, an acceleration period, a deceleration period and a stationary period. In the corrosion process of the Ni–P film in 1 mol/L HCl, the dissolving rate decreases with contact time in the initial 10 min and then approaches to a stable level of 0.12 nm/min. The wearing rate of the Ni–P film in Al 2O 3 polishing powder is much larger than the dissolving rate in 1 mol/L HCl and decreases slightly with time. The ESPS technique is an effective tool for in situ monitoring of the mass changes in electroless plating on quartz material.