The study on the permeability of lacquer film using a scientific and feasible testing method is significant for exploring the formation mechanism of waterlogged lacquer relics and the principle of their protective filling process. To study the permeability of natural lacquer film in the aqueous solution, the variation of electrochemical impedance spectroscopy (EIS) in a 3.5% NaCl aqueous solution with time, of samples prepared on iron substrates coated with three kinds of natural lacquer was investigated. The result shows that the lacquer film capacitance increased at extended time, until it reached an equilibrium value. The capacitance of each film decreased with the increase of layer number, and the soakage and penetration time increased with the increase of film thickness.