A doping method for forming quantum dots is disclosed, which includes following steps: providing a first precursor solution for a group II element and a second precursor solution for a group VI element; heating and mixing the first precursor solution and the second precursor solution for forming a plurality of II VI compound cores of the quantum dots dispersing in a melting mixed solution; and injecting a third precursor solution for a group VI element and a forth precursor solution with at least one dopant to the mixed solution in turn at a fixed time interval in order to form quantum dots with multi-shell dopant; wherein the dopant described here is selected from a group consisting of transitional metal and halogen elements. This method of the invention can dope the dopants in the inner quantum dot and enhance the emission intensity efficiently.