Disclosed by the present disclosure are Group II-III-V-VI quantum dots, preparation method therefore and quantum dot optoelectric device. The method for preparing Group II-III-V-VI quantum dots includes the following steps: S1, providing a first solution containing Group III-V quantum dot cores, or providing a second solution containing II-III-V quantum dot cores; S2, adding a second supplementary liquid to the first solution, or adding a first supplementary liquid to the second solution, and reacting to obtain Group II-III-V-VI quantum dot cores; wherein reacting a first mixture including a precursor of a first Group III element, a precursor of a first Group V element and a solvent at a temperature of 40˜100° C. and then adding a precursor of a first Group VI element and reacting to obtain the first supplementary liquid; or reacting a second mixture including a precursor of a first Group II element, a first Group III element, a precursor of a first Group V element and a solvent at a temperature of 40˜100° C. and then adding a precursor of a first Group VI element and reacting to obtain the second supplementary liquid.