Blind system identification is a fundamental signal processing technology, which retrieved a system unknown information from its output only. The method is particularly driven by an unknown input. This thesis makes more advanced research on the application of blind system identification method to the mechanical fault diagnosis, which combines the National Natural Science Foundation of China(No. 50775208) and the Natural Science Foundation of He'nan Educational Committee, China (No: 2006460005, 2008C460003)....