Abstract: By means of macroscopic examination, chemical composition analysis, metallographic examination, fracture analysis and so on, the fracture reasons of foundation bolts and connecting bolts of hydrogen compressor were analyzed. The results showed that the compressor frame was installed obliquely, resulted in the fracture of foundation bolts by shear stress; at last fatigue fracture occured in connecting bolts by shear stress and axial tensile stress caused by vibration and pre-tightening force of connecting bolts was more than the most allowable pretightening force. In addition, the secondary fracture reason was the material defects in bolts reduced the strength of bolts.