Based on the concept of treating waste with waste, this paper proposes a new idea to solidify the dredged sludge with the improved municipal solid waste incineration (MSWI) bottom ash. Laboratory tests were carried out to measure the moisture content, unconfined compressive strength and shear strength parameters of solidified dredged sludge. The results show that the best solidification effect is obtained when the pulverized powder and the unground powder of the MSWI bottom ash are mixed at 1∶1. Under the condition of the optimal mixture ratio, the unconfined compressive strength, cohesion and internal friction angle of the solidified dredged sludge increase with the increase of the curing times and the content of improved MSWI bottom ash, while the change trend of moisture content is on the contrary. When the content of the improved MSWI bottom ash is 35%, the unconfined compressive strength of solidified sludge after 28 curing days can reach 58.4.kPa, and the moisture content decreases from 67.4% to 38.0%, which proves the feasibility of using the improved MSWI bottom ash to solidify the dredged sludge.