Considering the problems of poor dynamic demand adaptability,the discreteness of design phases and long design cycles that generally exist in electromechanical products,the design stage of electromechanical products was studied using digital twin technology on the basis of design theory and methodology innovation,and the digital twin evolution method of electromechanical products design domain was composed of demand analysis,conceptual model evolution,structural model evolution,parametric model evolution and twin model verification.In addition,the optimization method of design-evaluation-feedback-iteration was used in aforementioned three evolution models respectively.Taking the traction elevator as an example,the feasibility of the digital twin evolution method of electromechanical products design domain was verified applying the vibration data of elevator for comparison and iteration during the verification process of twin model.