In this work there was developed a technique of the investigation of the back- scattering characteristics of the rough surfaces by the powerful pulsed laser irradiation of them. An experimental set up to measure these characteristics at a time resolution of~10^(–9) ñ is discussing the. The new experimental results are compared with the theoretical and experimental results of the authors obtains in stationary and quasi-stationary regimes of the surface irradation. It is making the deep wide analysis of the surface- radiation interaction processes that may fluence on the radial distribution of the back- scattering brightness coefficient indicatrisses of investigated surfaces beta(fi). It is pointed out that in non- stationary mixt of the laser surface irradiation the changes in beta(fi) may arise due to generation of surface electromagnetic waves initiated by the own laser surface irradiation and their subsequent interference with the probing and scattered laser radiation waves.