NOVELTY - Biologically reinforcing pre-treatment surplus sludge, comprises (a) taking a loop of cryopreserved Bacillus subtilis, inoculating into beef extract peptone liquid culture medium, aerobically culturing in a rotary shaker to obtain activated Bacillus subtilis; (b) inoculating a loop of the activated Bacillus subtilis into a beef extract peptone solid culture medium containing starch, culturing to obtain Bacillus subtilis A; and (c) adding Bacillus subtilis A into residual sludge of sewage secondary biological treatment process, and reacting.    USE - The method is useful for biologically reinforcing pre-treatment surplus sludge.    ADVANTAGE - The method: solves the problem of slow hydrolysis speed of the sludge anaerobic digestion process, ensures simple and safe operation with low energy consumption and good pre-processing effect of municipal sludge; ensures improved volatile suspended solids removal rate (15.1%), increased chemical oxygen demand (2734 mg/l) in the treated sludge supernatant and increased volatile fatty acids content (1080 mg/l); and the sludge treated by the method can be further processed by the anaerobic digestion process.    DETAILED DESCRIPTION - Biologically reinforcing pre-treatment surplus sludge, comprises (a) taking a loop of cryopreserved Bacillus subtilis, inoculating into beef extract peptone liquid culture medium, aerobically culturing in a rotary shaker at 30-40 degrees C under 150 rotations/minute for 28-35 hours to obtain activated Bacillus subtilis; (b) inoculating a loop of the activated Bacillus subtilis into a beef extract peptone solid culture medium containing starch, culturing at 30-40 degrees C for 30 hours to obtain Bacillus subtilis A; and (c) adding Bacillus subtilis A (0.2 parts) into residual sludge (1 part) of sewage secondary biological treatment process, and reacting at 30-45 degrees C under stirring speed of 100-150 rotations/minute for 30-40 hours; where the Bacillus subtilis in the step (a) is Bacillus subtilis 1.1413, which is preserved with an accession number CGMCC NO: 1.1413 at China General Microbiological Culture Collection Center, the liquid culture medium is prepared by autoclaving (in g) beef extract (5), peptone (5), sodium chloride (5), starch (10) and 1000 ml of water at 121 degrees C for 30 minutes, and its pH value is 7.2-7.4; the solid culture medium is prepared by autoclaving (in g) beef extract (5), peptone (10), sodium chloride (5), starch (10), agar (20) and 1000 ml of water at 121 degrees C for 30 minutes, and its pH value is 7.2-7.4.