Flexible assembly is characterized by the digitization, in the phase of the concurrent engineering, according to the idea of design for the flexible assembly, the key characteristics which influences the aircraft quality are defi ned. Through the analysis of the error accumulation, the key characteristics are decomposed to the components and process. Digital technology is used to distribute the tolerance, the tolerance information is added into the dataset of flexible assembly to coordinate the product and tooling’s manufacturing and checkout. By measuring and controlling the key characteristics of the components and process, the quality and effi ciency of the assembly could be conspicuously improved.