The preparation process and characteristics of soluble dietary fiber (SDF)were investigated during the liquid fermentation with Monascus Anka 3.4811, when okara, wheat bran and pear residue were used as substrates. The optimal fermentation conditions were obtained as followed: okara fermentation time was 7 d, solid-liquid ratio was 1∶15 (g/mL), inoculum amount was 13%; wheat bran fermentation time was 6 d, ratio of material to liquid was 1∶15 (g/mL), inoculum was 14%; pear residue fermentation time was 6 d, ratio of material to liquid was 1∶20 (g/mL), inoculum was 14%. With the fermentation, the solubility, water holding capacity and oil holding capacity of SDF were improved, and the functional properties were improved.