Abstract: China Electric Power Design Institute of China Power Engineering Consulting Group On the basis of gray correlation degree analysis of safety investment and security benefits in sub-division of coal mine，the bi-objective optimization model of minimum security costs and maximum safety degree is established With a case，the model maximizes the effectiveness of limited investment within security level It provides a reference for decision-making of safety investment in coal mine.

Key words: Coal mine, Safety investment, Grey correlation degree, Matlab, Optimization