Reasonable selection of grounding materials is the key factor to ensure the grounding system reliability. In order to optimize selection of grounding materials, conducted is contrastive analysis on the grounding performance of such materials as steel and copper and their influence on other buried metal pipelines. On the basis of theoretical analysis results and actual cases, proposed is an optimization measure, that is，copper product is used in substation grounding system of gas treatment plant and steel product is used in other area grounding system of gas treatment plant. This method can effectively improve the grounding system reliability, reduce the substation grounding resistance and weaken influence of the ground material on the buried metal pipelines, which has a good stability and economy and can be widely used in grounding system design of gas treatment plant in the future.