Abstract: SPSS distance analysis was used for investment decision analysis of 10 enterprises that have close investment scale. We find that coal enterprises often increase safety equipment renovation cost, safety technology and measures cost and safety engineering cost at the same time, but the enterprises are random in “software investment”. Based on real options theory, we introduce the concept of disproportion factor, comprehensively consider investment efficiency, accident probability, accident severity and the attitude of decision-maker, and build NPV-DF decision evaluation algorithm and safety measure investment evaluation system. Through repeated technical and financial evaluation, we ultimately establish optimal investment model.