In this paper, a composite curved beam structure used in high stiffness components of space launch platform is designed，and its mechanical properties are studied experimentally and numerically. Firstly, the static loading test of the curved beam is carried out by a computer controlled electronic testing machine. The load-displacement characteristic curves of the curved beam are obtained, and the equivalent elastic modulus is calculated. Based on ABAQUS finite element software, the finite element model of curved beam is established, and the numerical computations under different displacement loads are carried out. The experimental data are used to verify the numerical results. The calculated results are in good agreement with the measured results, and the errors are less than 10%. Then, the finite element model is used to calculate the longitudinal and transverse displacements of curved beams under different loads. It is concluded that the longitudinal displacement of curved beam is small, the transverse displacement is large, and the ratio of transverse displacement to longitudinal displacement is greater than 10. The effects of thickness of curved beam, width of clearance, and length of central straight beam on the mechanical properties of curved beam are studied, and the rules of the influence of different geometric parameters on the equivalent elastic modulus are obtained. This study provides a reference for the application of curved beams in the vibration isolation devices.