Abstract: In order to prevent spontaneous combustion of residual coal in gobs，we usually constructed fire dam in gobs．For the shortages of the existing technologies, we introduced a technology of fast building fire dam by fast curing coal ash slurry, and analyzed its technical features and infusion ways．In order to test the reliability of the technology，we selected 8617 face of a mine in Shanxi province．The results showed that the technology of fast building fire dam by fast curing coal ash slurry can be used for closing the gobs in coal mines with good effect．