Photolysis of aqueous solutions of phenol and п-chlorophenol at excitation by laser radiation with different wavelength and output density is studied. It is found that the mechanism of photolysis of aqueous solutions of phenols at excitation by high-power radiation of KrCl laser (222 nm, 30 MW/cm2) has some peculiarities as compared to their phototransformations at excitation by low-intensity radiation at a long-wave absorption band. This is connected with nonlinear excitation of the solvent by high-power UV laser radiation.