Abstract: By means of conventional hot-pressing, dry fiber was pressed to make into high density fiberboard. The temperature of its mat’ s central layer were measured and noted in the pressing process. Based on the data of experiments, the relations between the rising velocity of mat’ s central layer’ s temperature and moisture content of mats, thickness, density of panels, hot-pressing temperature were analyzed. The results shows: Before water in mats is vaporized, the higher the hot-pressing temperature is;or the thinner the panels is, or the lower the density is,the greater the growth speed of the central temperature is,while the effect of mat’s moisture content on it is very little;The higher the hot-pressing temperature i-s,or the thinner panels is,or the higher the density is, or the higher the mat’s moisture content, the higher the water’s vaporizing temperature is; The higher the hot-pressing temperature is, or the thinner panels is, or the lower the density or the less the moisture content of mats, the shorter the vaporizing time of the mat’s water is;The thicker panels is, or the lower the density is or the higher the mat’s moisture content, the lower the falling temperature is after water is vaporized, and hot-pressing temperature has no effects on it; After water is’ vaporized, the higher the hot-pressing temperature is, or the thinner the panels is or the lower the density is, or the higher the mat’s moisture content,the greater the growth speed of temperature is.