Abstract: The moisture-mildew-saltspray proofing design of shipborne optic-electronic equipment is an important mission for the shipborne optic-electronic equipment. It should be considered overall from the materials application, structure design, process engineering and so on at the time of the product development. In this paper the three-proofing issue of shipborne optic-electronic equipment was studied. The three-proofing design was detailedly introduced in optic lens, machine structure and electronics. The proper choice of material is the basis of the design. The rationality of the structural design is the key factor for moisture-mildew-saltspray proofing design of the shipborne optic-electronic equipment. It would improve the proofing capability farther that the correct use of the material modification, surface coating/depositing, encapsulation, insulation process and so on. It was proved by engineering practice that the design could make the shipborne optic-electronic equipment have excellent three-proofing performance and work steadily in sea climate environment for longer time.