The Business intelligence (BI) is to appear on various mature technology bases such as computer soft hardware, network, communication, decision-making, is one item technology used for handling magnanimous data. It requires to discovering the law from the various data resource (Database, Data Warehouse, Web etc.), and this will be mainly dependent on the data storehouse (DW), On-Line Analytical Processing(OLAP), data mining (DM). This paper presents the working state of the BI system in a retail enterprise, and elaborates the realization of a BI system and the effect of the practical application under the data environment of a complex business system. This paper also introduces the whole process of the BI project, including the proof of the BI system, the plan shaping, the design of data warehouses, the data mining and the frontier data presentation.