For better harmlessly treatment of papermaking sludge, a new technology for solidifying and stabling of sludge was studied. Papermaking sludge was solidified and stabilized by the solidifying agents including cement, powder fly ash (PFA) and cinder. The mechanical properties of solidified sludge block were evaluated by compressive strength, chemical oxygen demand (COD) and heavy metals concentration in the leachate from the solidified block were tested as well. When the solidifying agents has the following composition (cement 0.12kg/kg, PFA 0.02kg/kg and cinder 0.10kg/kg respectively), and the curing time was 6ds, the compressive strength of the solidified sludge blocks reached 360kPa. The results showed that cement and cinder were all positive in the compressed strength of sludge block. If they were mixed with PFA together, they could enhanced the solidification of organic and heavy metals in the sludge. Under this conditions, the COD in leachate from the solidified block was 115.7 mg/L, and the heavy metal concentration had reached the related national standards, after 6ds of curing time, water ratio of the solidified block kept from 35% to 40%, which met the prescribed standards of landfill.