Abstract: Based on grey correlation theory, an improved model of slope-correlation was established. Taking 70℃ as the boundary of high and low temperature in the process of coal spontaneous combustion experiment, the correlation degree between the influencing factors and the rate of oxygen consumption in various coal spontaneous combustion experiments with high temperature and low temperature was quantitatively studied, which was adopted as the index of measuring the impact of various factors on the coal spontaneous combustion. The results showed that volatile and porosity were the most important influencing factors of coal spontaneous combustion in high temperature period,whereas oxygen concentration had the greatest effect, moisture and ash had minimal effect on coal spontaneous combustion in low temperature period.