This text studies the real estate market comparison approach decision-making support system model library, including the residential real estate transaction case selecting models, the main characteristics factors determine model, the characteristics factors membership grade model, regional analysis model, the transaction date correction model; and uses the Windows for the operating system and ARCGIS9.2 as a basic geographic information system platform, sets up real estate valuation model library in the real estate market comparison approach decision-making support system with a city of urban basic geographic data as the test basic data, using C # 2005 + ArcObjects. Application practice shows that the valuation model has a higher credibility.