Abstract: Land treatment system is an effective technology for de harming and recycling wastewater in arid semiarid ecotone region.The design and operation of the land treatment system in Huolinhe Mining Field,Inner Mongolia showed that this region was well conditioned for extension of the land treatment technology,which should be based on recycling wastewater through slow rate filtration.Treatment of wastewater has to be combined with ecological construction.The application of wastewater is helpful in increasing stability of the complex eco system with mosaic structure,accelerating canopy closure and timber growing stock of the artificial forests,and improving the eco environment of the arid semiarid region.The social,economic and environmental benefits of the land treatment system are very remarkable.