Structural interchangeability does not only affect the maintainability and operability of aircraft, but also plays a crucial role in reducing manufacturing costs and final assembly cycle. Belly fairing is also called wing-tobody fairing, it locates in the wing-body joint area and its interface is very complex. Thus the assembly of the fairing strictures to fuselage can cost several months. The achievement of interchangeability can greatly reduce assembly time and improve the assembly efficiency. It is necessary to find an acceptable design compensation for interchangeability improvement also not increasing the manufacturing cost excessively. In this paper, a design scheme of joint with large clearance fit is proposed, and experiments are carried out to study the strength and failure modes. The results show that the strength of large clearance fit joint is slightly decreased comparing to joint with normal clearance fit and the failure modes of two kinds of joints are the same. Based on the study of this article, we propose a solution for belly fairing structures to achieve interchangeability, which can be a guidance for belly fairing design.