Melt treatment is one of the most important processes in the production of casting Al alloys. It is also a source of environmental pollution. A green and effective melt treatment with low environmental load (EI), which added with RE (Rare Earth) elements, was investigated in the paper. The research results show that this new treatment can modify, refine and purify the casting Al alloys simultaneously. Compared with the conventional treatment, the process is simplified, the metallurgic quality and mechanical properties are improved, and the environmental pollution which existed in the conventional treatment is solved thoroughly, so represented its wide applicative values.