A steam-explosion method was applied to the pretreatment of coal. Taiheiyo and Obed-Marsh coals were steam-exploded at 230℃ for 6min. The particle and pore size distributions were measured to examine the physical changes of the coals. The result suggests that this method is effective for the formation of small pores in the coal. When the coals were immersed into methanol before the explosion, the effect was enhanced due to the penetration of steam into the coal particles.