The frame of urban air quality prediction(diurnal)system which is the co-operative productions of Shanghai Environmental Monitoring Center and Shanghai Urban Environmental Meteorological Research Center, and its sub-systems of data collection, information exchange,prediction production and product promulgation were discribed.Five air models(or methods) used for daily urban air pollution index prediction and its forecasting precision were discussed. The result is that based on the analysis of local meteorological conditions, the air quality prediction in Shanghai is feasible through these models (or methods), and forecasting precision was satisfactory.