According to the collected fault data,the FMECA and fuzzy TOPSIS FMEA methods were studied on the feed system of the CNC grinder.Failure mode,fault cause analysis and hazard analysis were carried out by using FMECA method;according to the hazard degree of the failure mode to the system,the risk sequence of the failure mode was carried out.FMEA method based on TOPSIS was used to conduct fuzzy language evaluation of fault mode,and then it was quantified according to the introduced triangular fuzzy number,and a fuzzy decision matrix was constructed and standardized;the weight of the three risk factors based on the entropy weight method were determined and the weighted normalized fuzzy decision matrix was constructed.The TOPSIS was used to calculate the relative closeness of each failure mode and the risks were ranked.The results show that the feasibility of two methods have verified each other,and the FMEA method based on fuzzy TOPSIS is more accurate and practical.