Abstract: There are still some defects in the traditional wastewater biological disposal technology,when it has gone through 100 years' application. These defects are greater investment, much power and inconvenient management. In the wastewater purification system of varied organisms, wastewater is purified according to the metabolism of the food chain step by step. The system is composed of three disposal units of microbes, plants and aquatic animals. The organic matters in wastewater are digested and resolved into CO₂,H₂O,NH₄⁺,CH₄,PO₄^3-,etc. by anaerobe in the first unit. When wastewater passes through the second unit, everyone of them except CH₄ is absorbed by algae or plants and transformed into cells of plants by photosynthesis. In the third unit,the excessive microbes and algae are eaten by planktons or fish and transformed into animal albumen. Finally wastewater is purified, its effect can arrive at the level of third grade disposal. The wastewater purification technique of varied organisms is an ecological safe disposal technique to environment. It will be a new technique of 21st century. It has a good application foreground, especially is suitable for wastewater disposal in small town.