The newly developed refined diatom earth is a kind of “green”water treatment agent. On one hand, it has good treatment effect (as it has not only overcome the technological difficulties in industrial wastewater treatment, but also turned the wastewater into reusable resources, and the treated water can be directly reused); one the other hand, the sludge generated during wastewater treatment can be recycled or used for making other useful products. So refined diatom earth is an ideal product for developing clean production and cycle economy.