The problems of environmental pollution revealed the necessities of taking urgent precautions and tending towards the clean technologies for every branch of industry. Because the greatest part of textile finishing depends upon the wet processing and the chemical agents used are given to the environment without recycling, the works about clean technologies gained vital importance. The same problems occur in the wool finishing, too. Ozone usage is started to be tried in the finishing of wool fibers as the others as a new and enviromental friendly technology. The reducing of water consumption in finishing processes is also a great advantage. In this research, the degradation of ozone to oxygen, because of its unsteady structure was used in pretreatment of wool as a bleaching process.