Abstract: An operational grid system of soil moisture prediction system with the spatial resolution of 250m based on IDL language was developed in Beijing,basing on medium-term weather forecast,real-time observed soil moisture and MODIS satellite data.The system was based on the crop-soil water balance and the non-uniformity of spatial distribution of soil,vegetation and air conditions considered by grid information using RS and GIS techniques.The system was used by Beijing Meteorological Operation Service to provide useful directions of agricultural measures to be taken against the possible harmful effects of meteorological events.The results showed that the RS and GIS techniques could acquire grid effect of soil moisture prediction information and non-uniformity of the values of the parameters.And the system had clear technical flow,full functions and operational convenience.It could serve effectively in the agricultural drought monitoring and forecasting in Beijing and also in other areas where similar types of crop are grown.

Key words: Moisture prediction, Moisture prediction, Crop-soil water balance, RS and GIS, Grid, IDL language