Cotton stalk fibers were obtained through the steam-explosion pulping process and binderless fiberboards were produced from the fibers without any chemical additives. The effect of steam-exploded pressure on fiber dimension,chemistry components,and board properties was investigated in this paper. The results showed that higher steam pressure produced finer fibers with higher sugar,acids,and higher alcohol contents. It was also observed that the internal bonding strength of the binderless fiberboard was improved under higher steam exploded pressure. However,the mechanical property of the board decreased as steam pressure was increased.