The technology of data warehouse is introduced, and a real project is taken as an example to explain how to construct data warehouse and how to create a powerful data analysis system with PivotTable module based on the Web. With this system, the user can realize general data mining functions such as counting, filtering and regrouping. The system is supported by Microsoft OLAP Service and displayed with the technology of ASP. With the system, very flexible dynamic reports can come into view conveniently.