Function strains have been used for carrying out shake-flash reduction test of the second pond sludge which were derived from citric acid fermentation wastewater. The strains were acclimated by adding sterile original sludge with different concentrations. The optimum cultivate conditions of the strains processing were determined by the orthogonal and single factor tests. Experimental results indicated that the percentage of sludge MLSS reduction with the processing by W1-6 and W1-10 were improved obviously compared with the check sample after 4 cycles acclimation, which increased from 17.62% to 24.61% and 16.60% to 23.17%, respectively. The percentage of sludge MLSS and MLVSS reduction were more than 27% and 40% under the optimum cultivate conditions. The SCOD in sludge centrifugal supernatant were raised from 521.7mg/L to around 1700mg/L, and the SV₃₀ was dropped to 54%-57% from 91%. Therefore, the sludge reduction effect was obvious, and at the same time the sludge dewatering performance significantly improved.