Abstract: The paper introduced data production process of mining and metallurgical equipment in details,put forward a methodology of data quality engineering of fault diagnosis of complex mining and metallurgical equipment which can ensure veracity of fault diagnosis by improving data quality,namely the measure can reduce data variation through optimal design of anti-interference of data collection system(outline), and recognise data variation source and decrease and prevent from variation in use and maintenance(inline),in order to collect high-quality data of equipment state under bad mining and metallurgical environment and insure data reliability of fault diagnosis of equipment.Verification of practical example showed that the method can provide solution of data quality assuring,and can decrease false alarm or fail report.