Performance of high molecular weight polyvinylcarbazole (PVK) (M-n = 1,100,000) as an interlayer has been demonstrated in the green phosphorescent organic light emitting devices (PHOLEDs) using solution process. The PVK interlayer on the surface of PEDOT:PSS has a good film uniformity characteristic with homogenous low dissolution, thereby improving the charge injection in the emissive layer effectively. The performance of high molecular weight PVK interlayer was compared with the poly(2,7-(9,9-di-n-octylfluorene)-alt-(1,4-phenylene-((4-sec-butylphenyl)imino)-1,4-phenylene)) (TFB) interlayer. The maximum current and power efficiency values of 23.1cd/A, 9.8 lm/W were demonstrated using a PVK interlayer in the green PHOLED. The effect of high molecular weight PVK interlayer and the device structure by solution processing are provided with efficient and simple manufacturing.