We have fabricated an organic light-emitting devices with high efficiency and brightness utilizing thick layer of a starburst amine compound 4,4', 4"-tris{N,-(3-methylphenyl)-N-phenylamin}triphenylamine (m-MTDATA) as hole injection buffer layer. The brightness and the current efficiency were comparatively improved compared with those of the device without the buffer layer. The device with 10nm m-MTDATA act as buffer layer has max brightness was 18590cd/m(2) at 17 V, and the highest luminous efficiency was achieved 4.30cd/A, at 7V, which is nearly three times than that of the device without it.