Abstract: The gas explosion is one of the major disasters influencing the coal mine safety in production, coal dust can influence gas explosion limits. The influence to explosion limits of gas by high volatile coal dust was studied with 20 L spherical vessel. The experimental results showed that the explosion limits of gas would become quite lower when coal dust participated; and the explosion limits decreased to 12.8% when the 100 g/m³ coal dust was mixed into the sample. Near the lower explosion limits, coal dust can stimulate gas explosion, the explosion limits of gas would become quite lower too, when coal dust participated, and the explosion limits decreased to 3.1% when the 100 g/m³ coal dust was mixed into the sample.