Abstract: Water discharged from second-order wastewater treatment still contains some organic compounds which are hard to degrade, free chlorine, and some metals such as Hg, Ag, Ti, Cr. These compounds can be removed by adsorption, in addition, it also can remove colour and odour. The rate of removal from wastewater by adsorption and cost depend on adsorbents and wastewater. The adsorbent used most widespreadly is activated carbon. The research achievements on adsorption for wastewater treatment are relatively little, the research is not avtive. In recent more ten years, the research about adsorbents is superior in numbers; At the aspect of theory research on adsorption, Langmuir isotherms, Freundlich isotherms, Temkin isotherms (describing chemical adsorption) and BET model (describing physical adsorption) are researched and applicated most widespreadly.