This paper introduces the application of data mining technology in real estate market and develops an application flow both in theory and practical example. Firstly, The definition, application ethods were introduced and using flow of data mining in real estate was analyzed. Then Nanjing real estate market was taken as an example to illustrate how to use neural network--one of the data mining technologies to analyze and forecast real estate market. Finally, some problems about data mining technology was bring forward and prospect was discussed. The results show that data mining produces high prediction accuracy in real estate data analyses and market prediction.