Abstract: In the capacity expansion of pseudo-boehmite production unit, a belt filter is introduced to substitute the conventional plate-frame filter plus tank wash. It is found that the pore volume of product from this new production line is much lower than that from the conventional one. The effect of aging and drying conditions on the properties of pseudo-boehmite samples is studied in laboratory simulating the industrial production process and the obtained samples are characterized by XRD, N2 adsorption, DTA, FT-IR and TEM techniques. Test results show that both aging and drying conditions have great impacted on the pore structure of samples obtained. In the case of fast washing, due to lack of aging time, the crystallinity of material is low, if slow-drying (in oven) is followed, large pore volume pseudo-boehmite product with high crystallinity can be obtained; on the contrary, if fast drying (spray drying) is adopted, only poor quality product is obtained. However, prolonging aging time to increase the crystallinity of slurry prior to fast drying is also helpful for obtaining pseudo-boehmite product with large pore volume. Based on the above research results, measure of slurrying the filter cake from belt filter to prolong material aging time is proposed and put into practice on the industrial unit, since then large pore pseudo-boehmite is produced from the belt filter production line successfully.