Different types of organic quantum well structures have been grown by organic molecular beam deposition. Energy level and optical property of the quantum well are determined by cyclic voltammetry, optical absorption and photoluminescence. Cyclic voltammetry and optical absorption results indicate that PBD/ Alq3 multilayer can be classified as type Ⅰ, NPB/Alq3 and BCP/ Alq3 as type Ⅱ. The PL experimental results indicate that the structures of PBD/ Alq3 and BCP/ Alq3 exhibit complete energy transfer from PBD or BCP to Alq3, and the structures of NPB/Alq3 exhibit partial energy transfer from NPB to Alq3. The reason for energy transfer in organic quantum well structures is discussed in light of the theoretical and experimental results published in the literature.