Abstract: In this study, haze numerical model forecast system was established and run daily by coupling MM5, SMOKE and CMAQ models over Pearl River Delta which used the local sources emission inventories. The meteorological processes, gasphase chemistry, aqueous-phase chemistry, aerosol processes, heteorogeneous chemistry and deposition processes can be calculated in this modeling system. And the aerosol and extinction contribution, as well as processes of haze initiating, weakening, and intensifying, could be well simulated. By comparison with the forecast and site observations visibility,as well as the regional distribution of MODIS AOD,the spatial and temporal distribution of visibility could be well simulated by this modeling system during a typical haze process. Judging by the running annual business forecast, visibility forecasts were in good agreement with observations.The forecast was better in the dry season (haze season).In urban areas, the annual average TS score was up to 0.67, forecast efficiency EH was up to 0.89; In suburban districts, the TS was 0.37, the EH was up to 0.83. The study showed that, the model system had a good forecasting ability for haze and magnitude of visibility to achieve business operational requirements.