The FMECA method can effectively guide the reliability allocation of CNC machine tools.But in the analysis process,the influence of the randomness and fuzziness of decision-making experts,and the maintainability of subsystems is ignored.A reliability allocation method based on improved FMECA method and maintainability for CNC machine tools was proposed.In the process of hazardanalysis,the cloud model was used to quantitatively represent the evaluation values of decision-making experts,the impact of randomness and fuzziness on the evaluation results was solved effectively.During the analysis process,considering the influence of maintainability,an improved RPN method based on cloud models (C-RPN) was established to achieve reasonable allocation of reliability for the subsystems of CNC machine tool.Finally,the advantages of the proposed method were demonstrated by comparing with traditional methods.