Molybdenum(V) thiocyanate complex extracted by Tween-80, a non-ionic surface active agent, in chloroform has been studied. When the concentration of Tween-80 is 0.1%, extractive ratio can reach 94%, while tungsten(III) thiocyanate can not extracted in the same condition. Therefore, the two kinds of complexes can be separated very well. It enjoys a better extraction efficiency compared with petroleum ether or dimethyl sulfoxide and the advantage of low cost, no toxicity and no pollution. The extraction mechanism has been studied and may be a kind of extraction belonging to the category of supermolecular, which has not been reported publicly.