Abstract: The flow of the inlet of the ramjet engine is complex, and the structure of the inlet wall plate is very easy to induce aeroelastic problems under the requirements of lightweight structural design. In order to study the influence of aeroelasticity on the performance of the ramjet inlet, the aeroelastic wind tunnel test of the inlet was carried out. The stiffness design of the structure of the inlet lip and the internal inlet panel was carried out, and the influence of the aeroelasticity of the inlet tract on the performance of the inlet tract and the structural dynamics response characteristics under the high-speed flow condition were studied. The results of the wind tunnel test show that the maximum elastic deformation of the inlet lip structure is about 2.25 mm, accounting for 1.3% of the inlet’s lip width, resulting in a decrease of about 5% in the total pressure recovery coefficient of the inlet tract, an increase of about 10% in the flow coefficient of the inlet tract, and a significant change in the inlet performance. Under the action of complex shock waves, the internal wall plate structure of the inlet duct presents obvious static deformation characteristics. There is high-frequency vibration on the basis of static deformation, and the vibration frequency is close to the high-order mode frequency of the wall plate. The results of this paper show that aeroelasticity has a significant effect on the performance of ramjet engine inlet tracts. Therefore, the influence of aeroelasticity should be considered in the refined design of the air inlet aerodynamics and structure.