This paper focuses on the key issues of tool wear condition monitoring in the field of machining, and deeply discusses the application of digital twin technology in this aspect. This paper expounds the principle and architecture of digital twin technology, analyzes its specific methods in tool wear data acquisition, modeling, simulation, and real-time monitoring, and shows the significant advantages of this technology in improving the accuracy of tool wear monitoring and realizing predictive maintenance. At the same time, the challenges faced by digital twin technology in tool wear condition monitoring are discussed, and the corresponding development direction is put forward, aiming to provide theoretical reference and practical guidance for optimizing tool management by digital twin technology in the machining industry.