Aiming at flexible digital assembly process of aircraft large components, a 3D visual monitoring method of drilling process for aircraft wings is proposed based on real time onsite data in order to relieve the problems such as poorly openness of component local area, limited observation view of operators, lower level visualization of drilling process information. A data set of drilling system for onsite monitoring visualization is presented. A process for data integration between virtual and physical drilling scenario is described. Multiple 3D view management of virtual scenario and real time visualization of drilling hole feature are elaborated according to the actual requirements. A prototyping system for 3D visualization onsite monitoring of drilling process is developed based on the CAITA platform. By establishing network connection with onsite equipment servers, the system can real-time receive and display multi-dimensional information of drilling process intuitively and dynamically, which improves the onsite monitoring capability of aircraft large components drilling process.