The formation conditions of gold nanofilms on silicon (Si) substrate by galvanic replacement in a dimethyl sulfoxide (DMSO) solvent and their subsequent use for the fabrication of Si nanostructures by metal-assisted chemical etching (MACE) method were under study. It was found that the average size and number of Au nanoparticles increase with an increase in the reducible metal ion concentration from 2 to 8 mM HAuCl4 in DMSO, whereas the distribution of Au nanoparticles in height remains low for all concentrations of the reducible metal. In the temperature range 40 - 70°C, a different morphology of the deposited Au nanofilms observed. In particular, at 40 °C, the film is porous mainly homogeneous, whereas at a temperature of 50°C the film is rougher. The subsequent rise in temperature from 60°C to 70°C results in the formation of Au nanofilm with a discontinuous morphology. It was established that regardless of the morphology of deposited Au nanofilms, the Si nanostructures maintain a vertical orientation to the plane of the Si substrate during MACE-etching. The produced Si nanostructures were 1.5 - 2.5 μm in height and their average diameter ranged from 100 to 300 nm.