Abstract: In recent years, with the development of data warehouse and Web technology, more and more attention has been paid to multiple applications of the data in warehouse. However, data quality issue is one of the biggest obstacles to the success using of data warehouse project for many enterprises. So a data audit model is proposed and the relevant methods are studied in the study based on the characteristics of the telecommunications industry. Further, a three data layer audit method, consisted of audit mode data file level, record level and index level, is constructed during Extraction Transformation Loading (ETL) process. It can effectively improve the data quality of data warehouse.