In order to increase hydrogen ion concentration, hydrochloric acid was added in the etching liquid for the preparation of porous silicon used by electrochemical wet etching. The diameters of pores were constant and the depth linearly increased into constant with the concentration of hydrogen ions. The changes of the diameter and depth of pores were discussed on the basis of current burst model. The apertures formed in the initial stage of etching. In this stage the holes dominated the silicon corrosion, and the transport and consumption of the holes led to the aperture expansion and the formation of pore walls. The characters of holes were decided by silicon substrates and were not related to the concentration of hydrogen ions, so the apertures were constant. The increase of hydrogen ion concentration led to the acceleration until constant on the reaction rate of hydrogen displacement, so the system reaction rate was accelerated to a constant until it was limited by other reaction. The curve of pore depth - hydrochloric acid concentration remained constant after a linear increasing. Si-H contents increased with the pore depth in the certain range. Si-H₂ bonds dominated in the bonding type of Si-H_x (x=1, 2, 3).