Solution to many spatial decision-making problems

such as site selection or regional sustainable development

needs Spatial Decision Support System （SDSS） instead of Geographic Information System （GIS） because currently-available commercial GIS software Packages lack those capabilities for spatio-temporal distribution

prediction

simulation of spatial information

and interactive questioning between analysts and decision-makers. This paper summarizes two methods to establish a SDSS software. One is to generate a SDSS by coupling currently-available GIS software with analytic decision models. The other is to develop a true SDSS that has the integrated capabilities for management of spatial data and analytic models. The first method requires a shorter developing period and less cost than the second one. A SDSS based on the second method has a common interface and an integrated data structure

therefore

it is more efficient and easier to be used. The system

Decision Support System of Regional Agricultural Sustainable Development in China （DSSRASD） developed by the authors and our collaborators in 1995

is a true SDSS for agricultural sustainable development. A new data structure

Hyper Graph-based Data Structure （HBDS） is used to establish the base of DSSRASD in Borland C

++

for Windows. Furthermore

utilization of remote sensing and multimedia technologies enables the system to be used by decision-makers easily. At present DSSRASD is running well in the three pilot areas （Penglai city and Zhoucun County of Shandong province

Tongshan County of Jiangshu province）. Finally

the prospects of SDSS are discussed.