In response to the requirements for aircraft large component automatic and digital alignment and assembly, using advantage of the data connectivity and data value coming from the aircraft large component alignment and assembly process, a digital twin based technology framework for the aircraft large component alignment and assembly was proposed. Correspondingly, the technical process of the aircraft large component alignment and assembly was proposed and elaborated from four perspectives of data collection, model establishment, visual modeling and virtual to physical mapping. A light weight process has being used in the digital model of CATIA of the aircraft large component, then, a virtual space was built up based on Unity3D technology and the real time mapping of physical entities to virtual space was achieved by data collection and data central and application service. It provides a reference for the application of digital twin in the aircraft large component alignment and assembly.