Forecast system for origin environment quality of agricultural product was proposed based on the database technology, ArcGIS Server, Flex and model theory. Taking VS 2008 and Flash builder 4.6 as the development environment, the proposed system could be used for the query of agricultural environmental information, the spatial analysis of pollutant information, and the forecasting of farmland environmental pollution. Based on the time series characteristics of heavy metal pollution in origin environment, exponential smoothing forecasting model was built to predict the heavy metal pollution. According to the monitoring data of heavy metals from January 2010 to April 2013, six kinds of heavy metals concentration prediction models were established. The analysis results showed that the prediction accuracy of models were around 90%, which meant that the exponential smoothing model could better fit the variation of heavy metal pollution.