This study systematized synthetically to use internet GIS and real estate appraisal method in computing system for the real estate decision. First, indicated the method of using GIS and databases to appraise the real estate by using the cost approach. Second, used the artificial neural network to predict the change of land prices and the artificial neural network convinced us that it indicates easily the result of land prices without complicated processes. Third, examined land prices using the artificial neural network but there is limits for the land price prediction because of difficult data gathering. also, this study may heighten information levels of the real estate field according to 21th century information level if use actively a internet, information users who should pay much moneys in existent real estate decisions may can approach easily.