To improve the mechanical and thermal performance of the onboard interface of Tianwen-1’s high-resolution camera， the structural design is determined by using inputs of the fundamental frequency of the camera and the satellite temperature. First， the onboard interface support requirements of a Mars high-resolution camera are analyzed， and common support methods for the onboard interface of an optical remote sensor are introduced. Second， the relationship between the optical performance of the remote sensor and the onboard interface is established. The sensitivity matrix of the spatial position change of the interface to the mirror surface shape is determined by performing a Monte Carlo analysis， and the interface design parameters affecting the stiffness and thermal stability of the entire machine are identified. Then， analysis models of the different interface schemes are established， and the optimal interface design scheme is determined. Finally， the fundamental frequency and stability of the entire machine under the selected onboard interface scheme are determined by conducting experimental tests. The test results show that with this interface scheme， the first-order fundamental frequency of the entire machine reaches 58 Hz， which is considerably higher than that of the satellite， and the MTF before and after the vibration are 0.196 and 0.187， respectively. Furthermore， when the temperature change in the onboard interface is 20 ℃， the MTF before and after camera focusing are 0.173 and 0.223， respectively. This spaceborne interface analysis and design method， based on statistical analysis， can effectively determine the interface design input， and the kinematics support solves the design problem of the interface of Tianwen-1’s astronomical camera. The design ideas and test results have considerable potential in guiding the design of this type of load interface.