If the quantitative index of the methane explosion in coal mines before exploding can be calculated, the measure will be take to prevent the methane explosion. The methods using in the analysis of the fatalness of the methane explosion are almost qualitative analysis. In this paper the quantitative analysis of the fatalness of the methane explosion in coal mines is achieved on the basis of the research of the essence event probability with the method of fault tree analysis using the micro-computer. The practical example of the quantitative analysis of the fatalness of the methane explosion in coal mines is given.