Organic light-emitting diode (OLED) is considered to be a new genera tion of flat panel display due to many advantages,such as high efficiency and luminance,low drive voltage and light weight.Organic metal complexes based on 8-hydroxyquinoline are widely used du e to simple synthesis, high luminance and efficiency,as well as superior film morphology.The small mol ecule organic complex of Znq (DBM) was designed and synthesized with 8-hydroxyquinoline and 1,3-diph enyl-1,3-propanedione. Monochrome OLED was fabricated based on Znq (DBM) as emitting layer.The structur e of OLED is ITO/m-MTDATA (5nm)/NPB(40nm)/Znq(DBM) (60nm)/LiF(0.5nm)/Al(100nm),the turn -on voltage is 5V and the maximum luminance is 4575cd/m².Then an interla yer of BCP was introduced into OLED,and the performance of OLED is studied with the thickness of BCP.The structure of OLED with interlayer is ITO/m-MTDATA (5nm)/NPB(40nm)/BCP(x nm)/Znq(DBM) (60nm)/LiF(0.5nm)/Al(100nm ).When the BCP is 0nm,the EL color is greenish-yellow.When the BCP is 1nm,the EL color is white,the CIE coordinate is (0.29,0.33) and maximum luminance is 2231cd/m².But when the BCP is 5nm, the EL color is blue.The working mechanism of the OLED is also discussed in t erms of the performance and device structures.