Aiming at the assembly rework and repair problems caused by the poor assembly precision in assembly process of large aircraft fuselage components, the quality control technology for key assembly procedure of aircraft based on preassembly precision analysis is proposed. Firstly, the actual coordinate information of key control characteristic points (KCCPs) of components or in-process assembly parts is preprocessed, including coordinate system transformation, data compensation, data integration and format conversion. Then, according to the assembly process and measured data, an assembly procedure precision model based on measured data is established to perform the pre-assembly precision analysis. Finally, taking the fuselage panel assembly as an example, the laser tracker is used to obtain the measured information of the three-dimensional coordinates of KCCPs, and the processed data are used as the input deviation of the assembly precision prediction model for preassembly precision analysis, so as to realize the quality control of the fuselage panel.