Abstract: In order to obtain a lightweight and high-stiffness main board structure for lightweight space camera, a topologic optimization design method was presented. FE (Finite Element) based topology optimization which is created with the variable-density method is executed to find the optimum material distribution of initial design main board of space camera by maximizing the stiffness. Compared with that before the optimization, the main board structure reduces weight from 36.8 kg to 15.4 kg, loses 58.2 percent weight with the first-order natural frequency above 400 Hz. In order to check whether the main board's distributing of stiffness is rational, the Finite Element Method (FEM) is used to analyze the model of the main board. Finally, the 0.5 g vibration test shows that the first natural frequency of main board is 479.2 Hz, which is very close to the result of the FEM, the error is 1.86 %. The numerical results indicate that after adopting the topologic optimization design method, not only the design course is shortened, but also the main board structure weight is effectively reduced and the capability of the main board structure is enhanced also, which shows that optimized board structures can meet the system design requirements well.