Using water retention capability and oil-binding capability as indices, the effects of the factors such as insert spacing of colloid mill, ratio of liquid to solid and milling time on the indices were evaluated, and the optimal conditions of the modification were obtained by a Box-Behnken experiment. The results showed that the optimal modification conditions were: insert spacing of 13 μm, ratio of liquid to solid of 90∶1 (mL/g) and milling time of 7.5 min. After crushing under such conditions, the KPDF had an average particle size (D₅₀) of 58 μm, lower than that before modification by 94.42%; the KPDF possessed a water retention capacity of 12.47 g/g and an oil-binding capacity of 5.45 g/g, higher than those prior to modification by 136.09% and 63.34%, respectively. The swelling capacity, solubility and cation exchange capacity of the modified KPDF reached 11.56 mL/g, 15.70% and 23.10 mmol/g, respectively, higher than those prior to modification by 157.26%, 80.46% and 31.62%. The results indicate that the modification with colloid mill is significantly effective, and the modified KPDF has excellent functional and physicochemical properties.