This study proposes an optimization method to design the main baffle for suppressing the influence of stray light on the imaging performance of a space camera and satisfying the stringent requirements of small weight and high stability. Further, the position distribution of the vanes of the baffle is analyzed based on the graphical method. A multi-objective optimization model of the baffle is established with regard to minimum structural compliance and mass as well as the constraint of the fundamental frequency. The optimized dimension design of the baffle can be obtained. The mass of the baffle is 0.24 kg, and the lightweight rate is 38.6%. In addition, the dynamic vibration test of the baffle and stray light analysis of the system are conducted. The results denote that the relative error between the finite element analysis results and experimental data is lower than 15% and that the baffle exhibits good stray light suppression performance. This indicates that the performance parameters of the designed baffle satisfy the requirements; furthermore, the feasibility of the optimization method is verified.