Based on the theory of silicon electrochemical etching, porous silicon (PS) structure is prepared through electrochemical anodization method. The diffusion limited model and Si oxidation principle are used to discuss the influence of anodization conditions on PS properties. Firstly, the influence of HF on PS porosity, etching rate and corrosion interface roughness is researched. And then, the etching characteristics of PS at different current density are researched. The results show that when PS is prepared in the 2:3 mixture (by volume) of HF (49 wt.%) and ethanol etching solution, with the increasing of current density, porosity and etching rate increase gradually. In constant current density of 55 mA/cm2, the etching rate increases with the increasing of HF volume content, while the porosity of PS decreases. PS-Si interface roughness increases with the increasing of current density and HF volume content. It has a high interface roughness and cause a crack layer of porous silicon structure when mixture (by volume) of HF and ethanol is over 3:2, the light-emitting quality of porous silicon optics will be influenced seriously.