Abstract: Two numerical experiments were performed by using ECMWF limited area model in order to assess the impact of radiative processes on the onset of summer monsoon. The control experiment included all the model physics and another experiment had the radiative processes excluded. The simulated results show that:the radiative processes enhanced the monsoon currents and the associated vertical circulations over southern Asia continent, especially over Qinghai-Tibet Plateau. The build up of the "Plateau Monsoon Depresson" and the onset of Plateau rainny season are highly dependent upon the radiative processes.Through the cloud-radiation interaction, the "moist processes" were enhanced over the continent. More latent heat was released. The feedback of the physicalprocesses caused the strengthening of the monsoon circulation.