Moisture change of the moisture concentration zone in Ultra-depth Bed singtering is tested by Quartz interrupt tests, the results as follows: at the same bed depth with the sintering time prolonged, the average humidity and the maximum humidity of the moisture concentration zone increases, water evaporation speed is slow. With the bed depth increasing, layer resistance increases, the average humidity and the maximum humidity of the moisture concentration zone increased, the moisture concentration zone is liable to overwet, so the sintering bed depth rang from 700mm to 1000mm bed, the depth increasing 100mm, sinter moisture content which in The lower part of sintering machine can be reduced 0.24% ~ 0.32%, as the sintering permeability is taking into account.