Abstract:According to the principle of gray correlation analysis,a comparison data series are composed by collecting the ideal index values of multiple factors of deep pit foundation supporting scheme to affect decision making,meanwhile the reference data series are also organized by collecting the actual indexes with the same effect to the decision making of foundation pit. The optimizing method on the supporting scheme is presented based on the model of gray optimal theory and combining with the practical example. The proposed method is simple with clear concept,and can be easily applied to the practical projects.