Abstract: The ecological functions and environmental influence of wastewater land treatment engineering in Steppe region are reviewed in this paper． The succession and ecological safety of artificial forest communities in the condition of wastewater irrigation are analyzed also．The aspect and tolxgraphty are the key factors to foresmtbn in steppe region．The artificial fOrestS in valley or with enough irrigation grow quickly within 10～15 years，that are used as the base of wood and seedlings．Droughty sunny slope and half sunny slope are not suitable to forestation．