Abstract: In this paper,field emission scanning electron microscope(SEM),Rockwell hardness test,energy spectrum analysis(EDS),chemical composition test and other detection methods are used to analyze the fracture of the bearing outer ring,and judge the fracture form.The results show that the Rockwell hardness of the bearing outer ring is higher than the standard value,the chemical composition meets the requirements,and the fracture has the characteristics of brittle fracture,so it is inferred that the bearing outer ring has brittle fracture under the action of external stress.