With the gradual maturity and application of digital assembly technology, the interchangeability design, which adapts to digital quantity transfer, has significant practical significance for improving the efficiency of large aircraft control surface design, stabilizing assembly quality and reducing maintenance cost. Taking the interchangeability design of a certain type of aircraft control surface as the research object, according to the requirements of the con-trol surface interchangeability, the paper analyses the design points, and establish the interchangeability design process coordinated with digital assembly. The structural elements of the interchangeability design are analyzed from the configuration characteristics of the control surface. The technical approach to realize the interchangeabil-ity of the control surface is proposed, and the corresponding reference indexes are given. Combined with the test method of aircraft interchangeability, the aileron of a certain type of aircraft is taken as an example to analyze and design the interchangeability of the control surface, which is verified by the actual assembly inspection.