Thick-walled macroporous silicon arrays (MSA) were fabricated on n-type monocrystalline silicon wafer with resistivity 4~5 kΩ·cm by photo-electrochemical etching in HF solutions. The surface and cross-sectional morphologies of the MSA were assessed by scanning electron microscope. The electric field distribution around the prefabricated pits were simulated by finite element method. By comparing with the simulation, the evolution of surface morphology of the prepared MSA was studied with the changing process parameters such as electrolyte, illumination, and applied voltage. During the etching process, deviations are found for the macropores despite of that there existed a restriction resulted from the prefabricated pits. This is due to the comprehensive effect of electric field distribution and etching parameters. The simulation results show that the electric field distribution on the prefabricated pits is featured by shapes along silicon orientation [100] and [110] at different values. Due to the existence of the above favorable influence factor, the etching face may tend to change from (110) to (100), in case that the illumination increases, while the surface free energy of the etching electrolyte decreases, which may be resulted from the stimulation of additives ethanol and hexadecyl trimethyl ammonium chloride (CTAC). Therefore, the increase of the applied voltage can restrain the etching deviation, which is conducive to rapidly transform the prefabricated pits into pores, hence, to promote the formation of thick-walled macroporous silicon array.