Abstract: In order to find out the failure cause of the fan blades of a turbine cooler, macro and micro observation, friction trace analysis, hardness test, and strength check were carried out. It is found that that the first failure part is the fan-side bearing. On this basis, simulation analysis, load fluctuation test, hardness test, over-temperature test on bearing and no lubrication failure test were carried out to analyze the failure cause of the bearing. The results show that the bending deformation of the bearing caused the fan blades to scrape and then fracture. The deformation failure of the bearing was the higher temperature due to dry grinding for lack of lubricating oil, which was related to the defective maintenance method. Based on the results above, some measures were put forward.