Abstract: Pulp residue was used as raw material to prepare the dialdehyde cellulose(DAC) with sodium periodate oxidation method. The response surface method was used to optimize the preparation process of DAC. Then the microfibrillated cellulose (MFC) was prepared with dialdehyde cellulose through high-pressure homogenizer. Experimental results showed that when temperature, oxidant dosage and time corresponded to 48 ℃, 50% and 176 min respectively, the aldehyde group content of DAC would reach 947.38 μmol/g. After high-pressure homogenization treatment for 60 min, the average particle size of the MFC was 532 nm and the crystallinity was 27.13%. And MFC retained the structure of the cellulose, but the thermal stability was lower. The tensile strength and bursting strength of the paper could be increased 81.40% and 47.41%, respectively, whereas its air permeability was reduced by about 50% when adding 5% MFC in it. However, the opacity of paper was slightly improved when MFC as added.