Abstract: To develop the instrument and meter served in the marine climate environment ,in addition to consider the performance of conventional design, three-proof design is also one of the important links for the instrumentsand meters structure designerto consider. Through the analysis of the influence of damp, mildew, salt fog to the life of instruments and meters in the sea state, combined with the work in the practical design experience, the three-proof design methods and measures in the instrumentation structural design are summarized and concluded. These methods can effectively improve the protection ability of instrument equipment in Ocean environment.