Some say it was transportation modeling that led the revolution of GIS in the earlier 1970s. Now the new trend shows rapid development of modeling techniques inside of the desktop GIS (or GIS-T). ModelManager2000 is such a graphic user interface between the traditional modeling software and GIS--a dynamic extension to ArcView GIS Version 3.0+. Not only can planners create modeling scenarios using real GIS data in ArcView GIS; they can also import and export modeling/network data from/to the modeling software. The result of modeling can be displayed in the detailed street map. Our presentation will summarize the design and application of ModelManager2000.