The lack of effective methods to develop the product, process and operation models based on virtual and physical convergence leads to the poor performance on intelligence, real-time capability and predictability in production management. This paper proposes an approach of modelling and operations for the digital twin in the context of manufacturing. Firstly, the concept and extension of the digital twin in the manufacturing context are elaborated to provide the implementation methods of virtual-physical convergence and information integration for a factory. Secondly, the modelling approaches of product digital twins, process digital twins and operation digital twins are presented, then the interoperation mode between these digital twins are explained. Thirdly, to elaborate how to execute operations between product, process and resource, Automation Markup Language (AutomationML) is used for modelling a structural parts machining cell. Finally, the performance evaluation is provided to demonstrate the improvement of production efficiency by using the proposed approach.