The topology optimization design of a new type of instrument cabin is studied. The topology optimization model of the instrument cabin is built by HyperMesh. The topological optimization of the design space is solved by OptiStruct. To reduce the weight by 70%, the design scheme based on weighted stiffness maximization is obtained, and the polylactic acid resin sample of the instrument cabin is prepared by 3D printing. Comparison test shows that adopting the optimal design scheme based on weighted stiffness, with the minimum weight, the measured stiffness of mounting bracket in the X direction and -X direction are the highest, which achieves the initial design goal.