As known, the formation of pores on n-type Si is impossible due to deficit of holes. The holes play the main role in the pore formation in electrochemical reaction. In our previous paper [1] we have shown the possibility to transform p-type Si into n-type Si by LR. Therefore, it is possible to control the speed of chemical reaction, the distribution of pores and their size by LR. The aim of this study is to show the influence of powerful laser radiation on the formation of pores on a surface of p-Si exposed by electrochemical etching method. The experiments were carried out on p-type of the Si(B) commercial wafer. At the first stage samples were irradiated by pulsed N2 laser (λ=337nm, τ=5ns) at intensities: I1(area 1)> I2(area 2)> I3(area 3)> I4=70MW/cm2 (area 4). No morphological changes have been detected by Optical microscope and Atomic force microscope (AFM) studies after irradiation by LR. At the second stage, samples were electrochemically etched for 10 minutes in HF solution (48%) with ethanol in proportion 1:2. PL spectrum of the non-irradiated surface was shifted to the red part of spectra with maximum at λ = 650 nm and PL was observed by a naked eye under UV lamp. AFM study has showed the formation of pores on the etched surface except irradiated areas where n-type of the Si formed. After irradiation and etching, area 4 peals to pieces with thickness of 1 µm and porous Si is found below the pealing pieces. The possibility of electrochemical activity control has been shown. Formation of p-n junction on a surface of p-Si [2], p-Ge [3], InSb [4] and CdTe [5] crystals by laser beam speak in favour of the interstitial mechanism of n-type area formation. One more proof of p-type transformation into n-type Si has been provided.